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UNIVERSE  OF  CALtFORM* 


NEW  REPTILES  AND  STEGOCEPHALIANS  FROM  THE  UPPER 
TRIASSIC  OF  WESTERN  TEXAS. 


BY 

E.  C.  CASE 

Professor  of  Historical  Geology  and  Palaeontology  in  the  University  of  Michigan 


PUBLISHED  BY  THE  CARNEGIE  INSTITUTION  OF  WASHINGTON 
WASHINGTON,  OCTOBER,   1922. 


OF  CALIFORNIA 


CARNEGIE  INSTITUTION  OF  WASHINGTON 

PUBLICATION  No.  321 


Copies  of  this  book 

first  is" 
OCTl  9  19::i 


TECHNICAL   PRESS 
WASHINGTON,    D.  C. 


CONTENTS. 

PAGE 

Introduction 7 

The  Upper  Triassic  Beds  of  the  Borders  of  the  Staked  Plains 7 

The  Literature  of  the  Triassic  Vertebrates  of  North  America 12 

A  New  Genus  of  the  Stegocephalia,  Buettneria  perfecta 13 

Description  of  Desmatosuchus  spurensis  and  the  New  Suborder  Desmatosuchia 26 

A  New  Parasuchian,  Promystriosuchus  ehlersi 49 

New  Parasuchians,  Leptosuchus  crosbiensis  and  Leptosuchus  imperfecta,  from  Crosby  County, 

Texas 61 

Description  of  Isolated  Bones  of  Parasuchians 70 

Description  of  the  Remains  of  Dinosaurs 78 

Coprolites 83 

Incertae  sedis .84 


ERRATA. 


Page  21,  Fig.  3,  in  place  of  x'  read  x,  and  in  place  of  x  read  x'. 

Page  28,  line  24,  in  place  of  7A  read  7B. 

Page  44,  fifteenth  line  from  bottom,  in  place  of  "shown  in  figure  16A  and  B", 

read  "shown  in  figure  16E  and  F." 
Page  46,  line  5,  in  place  of  18C  read  figure  ISA. 
Page  61,  about  middle  of  page,  in  place  of  25A  read  25B. 
Plate  7,  K  and  L,  in  place  of  anterior  dorsals,  read  anterior  caudals. 


NEW  REPTILES  AND  STEGOCEPHALIANS  FROM  THE  UPPER 
TRIASSIC  OF  WESTERN  TEXAS 


BY  E.  C.  CASE 


M-\V  KK1TILKS  AM)  STEGOCEPHALIANS  FROM  THE  UPPER  TRIASSIC 

OF  WESTERN  TEXAS. 

BY  E.  C.  CASE. 


INTRODUCTION. 

By  aid  of  grants  from  the  Carnegie  Institution  of  Washington,  the  author 
has  been  for  a  number  of  years  continuously  at  work  upon  the  investigation  of 
the  vertebrate  fauna  of  the  Permo-Carboniferous  beds  of  North  America.  The 
sudden  and  complete  disappearance  of  this  fauna  (followed,  after  an  interval 
represented  by  barren  beds,  by  a  highly  specialized  Upper  Triassic  fauna)  has 
always  been  a  tantalizing  problem — the  more  so  as  the  barren  beds  between  the 
two  widely  different  faunae  are  practically  the  same,  in  all  the  implications  as  to 
climate,  mode  of  deposition,  and  terrestrial  conditions,  as  the  fossiliferous  beds 
above  and  below. 

The  interval  of  time  represented  by  the  barren  beds  is  just  the  interval  in 
which  was  developed  the  wonderful  Permian  and  Triassic  reptilian  life  of  South 
Africa,  Russia,  and  western  Europe.  A  few  very  uncertain  remains,  briefly  dis- 
cussed in  the  section  of  this  paper  dealing  with  the  Upper  Triassic  beds  of  western 
Texas,  suggest  the  possibility  that  something  of  the  Lower  Triassic  life  of  the 
Eastern  Hemisphere  reached  North  America.  For  these  reasons  the  barren  beds 
have  been  followed  and  searched  with  extreme  care  wherever  they  occur,  but  so 
far  no  trace  of  vertebrate  life  has  been  found  in  them.  While  engaged  in  such  a 
search,  the  author  learned  of  a  small  area  in  Crosby  County,  Texas,  which  has 
yielded  a  considerable  amount  of  Upper  Triassic  vertebrate  material,  most  of 
which  is  new.  The  present  paper  contains  descriptions  of  this  new  and  interesting 
fauna. 

The  author  takes  this  opportunity  to  thank  the  Carnegie  Institution  of  Wash- 
ington and  its  officers  for  the  continued  support  which  has  made  the  work  possible. 
Also,  he  wishes  to  acknowledge  his  obligation  to  Mr.  Clifford  Jones,  manager  of 
the  Spur  Farm  Lands  Company,  and  the  other  officers  of  the  Swenson  properties, 
for  permission  to  go  upon  the  lands  under  their  control  and  for  many  acts  of  kind- 
ness and  courtesy  which  rendered  the  task  of  collection  much  easier  and  con- 
tributed largely  to  the  success  of  the  work. 

THE  UPPER  TRIASSIC  BEDS  OF  THE  BORDERS  OF  THE 

STAKED  PLAINS. 

The  Upper  Triassic  beds  exposed  on  the  borders  of  the  Staked  Plains  in 
Texas  and  New  Mexico  present  the  same  puzzling  complex  of  terrestrial  and 
fresh-water  deposits  that  they  do  wherever  they  appear  in  the  other  Plains  and 
Rocky  Mountain  States.  No  definite  determination  of  continuous  horizons  is 
possible,  as  the  sequence  alters  rapidly  within  a  short  distance  and  there  are  many 


8  NEW  REPTILES  AND  STEGOCEPHALIANS  FROM 

lenses  and  intercalated  beds  of  small  extent.  Invertebrate  fossils  are  few,  limited 
to  Unios,  which  are  generally  so  poorly  preserved  as  to  be  indeterminate  specific- 
ally; frequently  there  is  an  abundance  of  fossil  wood  in  the  form  of  larger  or  smaller 
fragments,  but  none  has  been  determined.  An  attempt  to  determine  the  wood 
revealed  that  it  was  badly  rotted  before  fossilization  and  so  deeply  impregnated 
with  gypsum  as  to  destroy  the  cell  structure.  Knowlton's  catalogue  of  the  Meso- 
zoic  and  Cenozoic  plants  of  North  America  mentions  no  Triassic  plants  from  Texas, 
and  those  listed  from  New  Mexico  are  from  the  central  and  southern  portions. 
The  age  of  the  beds  must  be  determined  by  the  vertebrate  fossils,  and  these  indicate 
an  Upper  Triassic  stage,  approximately  equivalent  to  the  Keuper  of  Europe. 

On  the  borders  of  the  Staked  Plains,  as  in  the  other  regions  of  the  United 
States  where  the  Triassic  is  exposed,  there  seems  to  be  no  possibility  of  determining 
the  boundary  between  the  Permo-Carboniferous  beds  and  the  Triassic.  The  Red 
Beds  are  apparently  continuous  across  the  interval,  and  the  connecting  beds  are,  so 
far  as  known,  entirely  devoid  of  any  evidence  of  life.  It  is  in  this  connecting  series 
of  beds,  representing  the  period  of  the  great  development  of  reptilian  life  in  the 
late  Permo-Carboniferous  and  the  early  Triassic  in  South  Africa,  that  some  repre- 
sentation of  that  life  should  appear  if  it  were  present  in  North  America.  Because 
of  this  fact  the  transition  beds  have  been  repeatedly  searched  with  the  greatest 
care,  but  as  yet  nothing  has  been  found.  The  only  remains  that  suggest  the  pres- 
ence of  anything  like  the  South  African  forms  in  North  America  are  the  prob- 
lematical fossil  found  in  West  Virginia,1  200  feet  below  the  base  of  the  Pittsburgh 
coal  bed  and  the  base  of  the  Monongahela  Series,  in  Braxton  County,  West  Vir- 
ginia, named  Pareiasaurus(?)  henningi  by  I.  C.  White,  and  the  forms  described 
by  Williston,  from  a  few  poorly  preserved  bones,  as  Eubrachiosaurus  and  Brachy- 
brachium,  from  the  Popo  Agie  beds  near  Landor,  Wyoming.  The  first  of  these 
Williston2  regarded  as  belonging  near  to  Tapinocephalus  or  Phocosaurus,  and  Dr. 
Broom,  in  conversation  with  the  author,  stated  his  opinion  that  it  was  Deino- 
cephalian  in  its  affinities.  Here,  also,  should  be  mentioned  the  humerus,  described 
by  Lucas  as  Placerias  hesternus,  from  the  Triassic  near  Tanner's  Crossing,  Little 
Colorado  River,  Arizona.3  These  remains  are  far  too  little  known  to  permit  of 
any  conclusion  being  drawn  from  them,  and  they  do  not  occur  in  the  transition 
beds,  but  below  and  above  them. 

The  Triassic  beds  of  the  borders  of  the  Staked  Plains  have  been  divided  by 
Drake4  into  three  parts,  and  his  divisions  are  recognizable  in  a  broad  way,  but 
rarely  can  any  definite  boundaries  be  assigned  to  the  divisions,  nor  can  the  pro- 
visional separation  made  in  one  place  be  carried  satisfactorily  for  any  distance. 
Drake  described  his  three  divisions  as  follows: 

1  Case,  E.  C.,  Notes  on  the  Possible  Evidence  of  a  Pareiasaur-like  Reptile  in  the  Coneraaugh  Series  of  West 

Virginia,  West  Virginia  Geological  Survey,  Braxton  and  Clay  County  Report,  p.  803,  1917. 

2  Williston,  S.  W.,  Notice  of  Some  New  Reptiles  from  the  Upper  Triassic  of  Wyoming,  journal  of  Geology, 

vol.  xii,  p.  690,  1904. 

3  Lucas,  F.  B.,  Proceedings  U.  S.  National  Museum,  vol.  27,  p.  194,  pi.  iv,  1904. 

1  Drake,  N.  F.,  Stratigraphy  of  the  Triassic  Formation  of  Northwest  Texas,  Third  Annual  Report  Texas 
Geological  Survey,  p.  227,  1892. 


THE  UPPER  TRIASSIC  OF  WESTERN  TEXAS.  9 

"Stratigraphy. — The  following  classification  or  grouping  is  not  intended  as  a  cor- 
relation with  any  other  Triassic  beds,  but  only  to  apply  to  the  Dockum  beds  over  the 
area  examined.  The  Dockum  may  be  divided  into  three  beds,  though  some  localities 
show  more,  that  are  more  or  less  well  marked.  *  *  *  These  three  main  beds  are  as 
follows:  A  lower  bed  of  sandy  clay,  which  is  from  0  to  150  feet  thick;  a  central  bed  or 
beds  of  sandstone,  conglomerate,  and  some  sandy  clay,  which  is  from  0  to  235  feet  thick; 
an  upper  bed  of  sandy  clay  and  some  sandstone,  which  is  from  0  to  300  feet  thick.  While 
these  groups  represent  the  different  geological  horizons  over  most  of  the  Triassic  area, 
there  is  nevertheless  at  some  places  a  thinning  out  of  the  one,  and  a  thickening  of  another, 
which  shows  that  at  the  same  time  the  conditions  of  deposition  were  somewhat  different 
at  different  localities.  The  same  geological  horizon  is,  therefore,  more  or  less  represented 
in  other  beds  than  that  which  generally  represents  it.  Then,  while  these  beds  do  not 
absolutely  represent  geological  horizons,  they  do  so  approximately  and  are  so  well 
marked  as  to  be  of  stratigraphical  value." 

On  the  east  side  of  the  Staked  Plains  the  lower  beds  are  red  sandy  shales  which 
may  be  traced  from  the  Canadian  River  southward  to  where  they  disappear 
beneath  the  Cretaceous  and  younger  deposits  south  of  Big  Springs,  in  Howard 
County.  These  beds  shade  downward  indefinitely  into  the  Double  Mountain  beds 
of  the  Permo-Carboniferous.  The  author  has  repeatedly  crossed  the  line,  in 
every  county  of  Texas  where  it  lies,  from  the  Canadian  River  on  the  north  as  far 
south  as  the  Triassic  appears,  and  has  been  unable  to  draw  any  line  that  can  be 
used  to  separate  the  two  formations.  In  passing  from  the  towns  Seymour,  Vernon, 
Haskell,  Anson,  and  Abilene  westward  to  the  Triassic  at  the  base  of  the  Plains, 
the  same  indefinite  boundary  is  crossed.  The  red  beds  grow  more  shaly,  and  in 
general  there  is  an  increase  in  the  amount  of  gypsum,  which  may  occur  in  beds 
from  a  few  inches  to  as  much  as  3  feet  thick,  or  may  be  in  fine  seams  running  in 
all  directions  through  the  red  sandy  clay.  The  same  condition  is  found  in  the 
breaks  of  the  Canadian  River  and  in  the  great  canyons  which  penetrate  into  the 
Plains  in  Randall,  Armstrong,  Swisher,  and  Briscoe  Counties.  Similar  conditions 
prevail  wherever  these  two  formations  come  together  in  New  Mexico,  Arizona,  or 
Wyoming  and  the  adjacent  States. 

In  the  vicinity  of  Dickens,  in  Dickens  County,  where  the  transition  beds  are 
beautifully  exposed  in  the  Croton  Breaks,  2  miles  directly  east  of  the  town,  the 
intermediate  series  is  terminated  above  by  a  few  feet  of  yellowish  and  bluish  clay 
which  is  overlain  by  a  considerable  thickness  of  grit  and  conglomerate,  such  as  is 
described  by  Drake  in  his  middle  division  of  the  Dockum  beds.  The  conglomerate 
and  the  resulting  gravel,  which  in  many  places  covers  the  surface,  are  generally  very 
easily  distinguished  from  the  grits  and  gravel  derived  from  the  overlying  Tertiary 
beds  of  the  Plains  by  the  large  amount  of  brownish,  semiangular,  indurated  clay 
as  opposed  to  the  dominant  whitish,  well-rounded  quartzite  of  the  upper  beds. 
The  Triassic  conglomerate  is  typically  shown  at  Dickens,  but  can  be  traced  from 
that  point  as  far  as  the  Canadian  River  on  the  north  and  beyond  Big  Springs  on 
the  south.  At  Dickens  in  Dickens  County,  Roaring  Springs  and  Matador  in 
Motley  County,  and  on  the  section  through  Quitaque  to  Tulia  in  Hall,  Briscoe, 
and  Swisher  Counties,  this  grit  and  conglomerate  lies  directly  beneath  the  Tertiary 


10  NEW   REPTILES   AND    STEGOCEPHALIANS  FROM 

cap-rock.  At  Spur,  a  few  miles  south  of  Dickens,  it  has  the  same  position,  forming 
the  hill,  in  the  north  part  of  the  town,  upon  which  the  water-tower  is  located,  and 
.  is  easily  traceable  in  the  small  elevations  which  can  be  seen  in  all  directions  for 
miles  from  that  point.  West  of  Spur  it  is  the  surface  rock,  appearing  at  intervals 
through  the  surficial  clays  and  sands  to  within  a  few  miles  of  the  Blanco  or  Catfish 
River,  where  the  lower  formations  are  again  visible  in  the  breaks.  On  the  east 
side  of  the  river  the  Triassic  is  much  obscured  by  the  accumulation  of  wind-blown 
sand,  but  on  the  western  side  the  bluffs  are  prominent  and  stand  out  as  conspicu- 
ous features  similar  to  the  bluffs  at  Dickens.  Such  a  prominence  is  Cedar  Moun- 
tain, between  the  forks  of  Sand  Creek.  From  the  summit  of  these  bluffs  the  hand- 
level  shows  that  the  tops  of  the  hills  are  approximately  on  the  same  level.  The 
beds  below  the  conglomerate  cap  in  this  region  are  decidedly  different  from  those 
shown  in  the  Croton  Breaks  east  of  Dickens;  there  is  much  less  of  the  deep-red 
clay  and  relatively  little  gypsum.  The  beds  are  composed  of  light-red  or  yellowish 
clay  in  most  of  the  exposures.  Though  there  is  considerable  continuity  in  the 
beds,  there  is  a  decided  irregularity  of  deposition  exposed  in  the  breaks  of  Holmes, 
Sand,  and  Davidson  Creeks  near  Cedar  Mountain;  here  there  are  frequently 
lenses  and  intercalated  beds  of  light  cream-colored  clay,  light-bluish  clay,  and 
light-red  clay,  with  abundant  irregular  concretions  and  nodules.  By  far  the 
greater  number  of  the  beds,  and  uniformly  those  which  are  at  all  regular  in  their 
deposition,  are  totally  barren  of  fossils.  It  is  only  in  the  irregular  beds  which 
were  evidently  deposited  in  stream-channels  and  local  pools  that  any  remains  are 
found.  It  is  evident  that  this  area,  which  is  so  different  from  that  of  the  Croton 
Breaks,  is  the  site  of  some  great  stream-channel  and  flood-plain. 

Unfortunately,  only  a  small  area  is  exposed  in  the  breaks,  and  a  careful  search 
of  the  whole  eastern  side  of  the  Plains  has  revealed  no  similar  locality.  Water- 
worn  fragments  of  bone  frequently  appear  in  the  conglomerate;  some  were  collected 
as  far  south  as  the  vicinity  of  Slaughter's  Ranch,  18  miles  southwest  of  Post  City 
in  Garza  County,  and  traces  of  bone  were  found  east  of  Big  Springs,  but  it  is  evi- 
dent that  the  areas  where  vertebrate  fossils  may  be  collected  in  any  quantity  and 
in  a  usable  state  of  preservation  are  very  limited  on  the  eastern  side  of  the  Plains. 

The  exposures  of  the  Triassic  in  the  breaks  of  the  Canadian  River,  in  the 
northern  part  of  the  Plains,  show  a  more  or  less  uniform  series  of  red  beds,  clays, 
and  sandy  shales,  with  occasional  bands  and  veins  of  gypsum  beneath  the  conglom- 
erate. These  beds  can  not  be  exactly  located  in  Drake's  series,  but  appear  to  be 
the  ones  located  in  his  upper  division,  though  Permo-Carboniferous  vertebrates 
have  been  reported  from  the  vicinity  of  Plemons  in  Hutchins  County,  and  the 
Texas  Geological  Survey  has  mapped  Permo-Carboniferous  in  the  western  part  of 
Oldham  County. 

On  the  western  side  of  the  Staked  Plains  a  splendid  view  of  the  exposures  of 
the  Triassic  can  be  had  from  the  edge  of  the  cap  just  west  of  Adrian  in  Oldham 
•County.  From  this  point  it  is  possible  to  see  a  large  area  of  the  breaks  in  the 
upper  part  of  the  Canadian  Valley  and  much  of  the  area  to  the  south,  almost  to 
Glen  Rio  on  the  Texas-New  Mexico  line.  The  land  is  roughly  rolling  and  much 


THE   UPPER   TRIASSIC   OF   WESTERN   TEXAS.  11 

of  it  is  grassed,  so  the  exposures  are  limited  in  extent;  but  they  are  uniformly  of 
red  clay  and  red  sandy  shale,  with  occasional  layers  of  more  or  less  heavy  brown 
sandstone  and  thin  beds  of  grit  or  conglomerate.  Throughout  this  area  fragmen- 
tary remains  of  Phytosaurs  and  Stegocephalians  occur  in  small  quantity.  The 
rolling  country  continues  westward  to  and  beyond  Tucumcari  in  Quay  County. 
About  5  miles  west  of  San  Jon,  in  Quay  County,  there  is  an  area  of  river  deposits 
with  beds  of  conglomerate,  heavy  sandstone,  loose  gravel,  and  clay;  the  change  in 
the  character  of  the  beds  is  reflected  in  the  nature  of  the  surface,  for  the  region 
is  locally  known  as  the  Bad  Lands.  In  this  limited  area  remains  of  Phytosaurs 
and  Stegocephalians  occur,  similar  to  those  found  in  Crosby  County,  Texas,  but 
in  far  smaller  number  and  in  a  poorly  preserved  condition.1  Beyond  San  Jon  the 
surface  of  the  country  again  becomes  more  regular,  reflecting  the  more  uniform 
character  of  the  beds  beneath. 

At  Mount  Tucumcari  and  along  the  west  front  of  the  Plains  there  is,  in  gen- 
eral, a  more  uniform  sequence  of  the  beds  than  on  the  east  side.  A  heavy  mass  of 
red  clay  and  red  sandy  shales  is  overlain  by  a  second  heavy  bed  of  sandstone  which 
may  be  white,  as  directly  west  of  Montoya,  or  brownish  farther  to  the  west  and 
south,  typically  exposed  at  Cuervo,  in  Guadalupe  County.  These  dominant  heavy 
beds  of  clay  and  sandstone  are  frequently  interrupted  by  locally  developed  beds 
of  lighter-colored  clays  and  sands,  white,  yellow,  or  blue,  in  which  poorly  preserved 
fragments  of  bones  occur  in  limited  amount.  The  same  character  of  the  beds  is 
found  as  far  west  as  Santa  Rosa,  in  Guadalupe  County,  and  as  far  south  as  beyond 
Roswell.  East  of  Roswell  the  red  beds  contain  much  more  gypsum  than  those 
farther  north,  and  no  remains  of  vertebrates  have  been  found  in  them. 

A  reconnaissance  from  Montoya  westward  through  Isidor,  Buxton,  and  Cabre 
Springs  and  up  the  Conchas  Canyon  to  Las  Vegas  showed  that  the  beds  retained 
a  similar  character  until  they  disappeared  beneath  the  Cretaceous.  It  is  evident 
that  the  great  bulk  of  the  Triassic  beds  revealed  on  the  borders  of  the  Staked  Plains 
and  in  eastern  and  central  New  Mexico  were  deposited  under  conditions  unfavorable 
to  the  preservation  of  vertebrate  fossils.  The  more  uniformly  deposited  beds  of 
clay  and  shale  were  apparently  laid  down  in  deep  water  or  in  water  far  from  the 
shores;  it  is  only  in  the  disturbed  beds,  which  bear  evidence  of  having  been  de- 
posited by  great  flood  washes,  that  the  remains  of  animals  and  plants  are  found. 
Such  remains  are  usually  badly  broken  and  water-worn;  occasionally  good  specimens 
will  turn  up,  as  evidenced  by  the  presence  of  a  skull  of  a  Phytosaur  preserved  in 
the  University  of  Chicago,  which  was  obtained  from  the  School  of  Mines  at  Socorro, 
New  Mexico,  and  said  to  come  from  near  Santa  Rosa,2  and  from  some  remains 
secured  by  the  author  near  Carthage,  Socorro  County.  It  is  only  in  such  rare 
occurrences  as  the  section  of  some  large  river  flood-plain,  such  as  occurs  in  eastern 
Crosby  County,  Texas,  that  good  material  will  be  found.  The  rarity  of  such  occur- 
rences is  shown  by  the  experience  of  the  author,  who,  in  four  trips  in  the  regions 
mentioned,  has  found  only  the  single  exposure. 

1  For  a  more  detailed  description  of  the  Bad  Lands  west  of  San  Jon,  see  an  article  by  the  author  in  the  Journal 

of  Geology,  vol.  XH,  No.  3,  1914. 
*  Mehl,  M.  G.,  A  New  Phytosaur  from  the  Trias  of  Arizona,  Journal  of  Geology,  vol.  xxx,  p.  144,  1922. 


12  NEW  REPTILES  AND  STEGOCEPHALIANS  FROM 

THE    LITERATURE    OF   THE   TRIASSIC   VERTEBRATES   OF 

NORTH  AMERICA. 

Our  knowledge  of  the  Triassic  vertebrate  life  of  North  America  is  so  limited 
that  it  is  not  yet  time  to  attempt  a  summary  statement  of  the  material  at  hand, 
but  it  will  not  be  amiss,  as  a  step  in  progress,  to  list  the  main  articles  which  have 
from  time  to  time  partially  reviewed  the  work  done  up  to  the  time  of  their  appear- 
ance. The  bibliographies  in  these  articles  will  lead  to  the  original  publications. 

1902.  HAY,  O.  P.    Bibliography  and  catalogue  of  the  fossil  vertebrates  of  North  America.     Bulletin  No.  179,  United 
States  Geol.  Survey. 

1905.  BRANSON,  E.  B.     Structure  and  relationships  of  American  Labyrinthodontida;.     Journal  of  Geology,  vol. 

xm,  No.  7. 

Contains  critical  review  of  known  Triassic  Stegocephalians  from  North  America  and  description  of  a 
new  genus,  Anaschisma. 

1906.  MCGREGOR,  J.  H.     The  Phytosawia,  with  especial  reference  to  Mystriosuchus  and  Rhytidodon.      Memoirs 

American  Mus.  Nat.  Hist.,  vol.  ix,  pt.  11. 

Contains  a  list  and  critical  review  of  genera  and  species  of  North  American  Phytosauria,  and  a  bib- 
liography. 

1906.  HUENE,  F.  v.     Ueber  die  Dinosaurier  des  Aussereuropaeischen  Trias.     Geologische  und  paleontologische 
Abhandlungen,  N.  F.,  Bd.  vm,  Hft.  2. 

Contains  a  critical  review  of  the  genera  and  species  of  the  Triassic  Dinosaurs  of  North  America,  with 

a  bibliography. 
1911.  HUENE,  F.  v.     Beitrage  zur  Kenntnis  und  Beurtheilung  der  Parasuchier.     Geologische  und  paleontologisch  c 

Abhandlungen,  N.  F.,  Bd.  x,  Hft.  1. 

1911.  EASTMAN,  C.  H.     Triassic  fishes  of  Connecticut.     Bulletin    18,  Geological  and  Natural  History  Survey, 
State  of  Connecticut. 

Contains  a  critical  revision  of  the  Triassic  fishes  of  the  northeastern  United  States. 
1915.  MEHL,  M.  G.     The  Phytosauria  of  the  Trias.     Journal  of  Geology,  vol.  xxm,  Feb.-Mar. 

Contains  a  description  of  new  forms,  a  review  of  known  genera  and  species,  and  a  bibliography. 
1915.  LULL,  R.  S.     Triassic  life  of  the  Connecticut  Valley.     Bulletin  24,  Geological  and  Natural  History  Survey, 
State  of  Connecticut. 

Contains  a  critical  discussion  of  the  vertebrate  fossils  of  the  Triassic  of  the  northeastern  United 

States,  and  a  bibliography. 

1920.  CASE,  E.  C.     Preliminary  description  of  a  new  suborder  of  phytosaurian  reptiles,  with  a  description  of  a  new 
species  of  Phytosaurus.     Journal  of  Geology,  vol.  xxvm,  Sept.-Oct. 

Contains  a  description  of  the  new  suborder  Desmatosuchia,  the  genus  and  species  Desmatosuchus 
spurensis  and  Phytosaurus  doughtyi. 

1920.  CASE,  E.  C.     On  a  very  perfect  thoracic  shield  of  a  large  labyrinthodont  in  the  geological  collections  of  the 

University  of  Michigan.     Occasional  Papers  of  the  Museum  of  Zoology,  University  of  Michigan,  Ann 
Arbor,  Mich.     No.  82. 

Contains  a  description  of  the  clavicles  and  interclavicle  of  Metoposaurus  jonesi. 

1921.  CASE,  E.  C.     A  new  species  of  Ceratodus  from  the  upper  Triassic  of  western  Texas.     Occasional  Papers  of  the 

Museum  of  Zoology,  University  of  Michigan,  Ann  Arbor,  Mich.     No.  101. 

Contains  a  description  of  a  tooth  of  a  new  species  of  Ceratodus.  C.  dorothece. 

1922.  MEHL,  M.  G.     A  new  Phytosaur  from  the  Trias  of  Arizona.     Journal  of  Geology,  vol.  xxx,  p.  144,  1922. 

Contains  a  description  of  a  new  form  Phytosaurus,  Machceroprosopus  andersoni. 

The  few  papers  published  in  1920,  1921,  and  1922  are  later  than  any  summary 
papers  and  are  inserted  to  bring  the  literature  up  to  date. 


CASE 


PLATE   I 


THE   Ul'I'Kli    TRIASSIC    OF   WESTERN    TEXAS.  13 

A  NEW  GENUS  OF  THE  STEGOCEPHALIA,  BUETTNERIA  PERFECTA. 

The  specimen  here  described,  No.  7475,  University  of  Michigan,  was  found  in  the 
breaks  of  Sand  Creek  just  south  of  Cedar  Mountain,  in  Crosby  County.  It  lay  in  a 
dark-red,  mud-lump  conglomerate  with  some  finer  material,  the  deposit  of  an  old  river- 
wash.  The  undistorted  skull  is  unique  in  the  perfect  preservation  of  the  bones  and  the 
minutiaj  with  which  the  osteological  details  may  be  traced.  The  matrix  was  readily 
removed  from  the  bones  of  the  lower  surface,  leaving  them  clean  and  white,  except 
where  stained  red  or  brown  by  iron.  The  rugose  upper  surface  was  less  readily  freed, 
but  the  matrix  came  away  very  clean,  revealing  the  pits  and  ridges  and  all  the  details 
of  the  sutures  and  the  slime-canals.  There  is  no  distortion  of  the  bones  of  the  upper 
and  lower  surfaces,  but  the  edges  of  some  of  the  slender  bones  which  form  the  walls  of 
the  brain-case  are  slightly  crumpled  and  injured  by  decay.  No  parts  are  missing 
from  the  upper  surface  except  the  major  part  of  the  left  squamosal,  the  extremities  of 
the  tabulare,  and  the  extreme  posterior  tip  of  the  right  maxillary.  On  the  lower  surface 
a  part  of  the  distal  end  of  the  left  pterygoid  is  missing,  there  is  no  trace  of  the  stapes, 
and  the  otic  opening  is  extremely  large;  for  reasons  given  in  the  body  of  the  paper  it 
is  believed  that  this  region  was  largely  cartilaginous. 

The  upper  surface  of  the  skull. — The  form  and  arrangement  of  the  various  elements, 
the  position  of  the  slime-canals,  and  the  character  of  the  sculpture  are  shown  in  figure 
1  A,  and  plate  1,  fig.  A,  and  dp  not  need  extended  discussion.  The  general  resemblance 
to  the  skull  of  Anaschisma  from  the  Popo  Agie  beds  of  Wyoming  is  apparent,  but  the 
arrangement  of  the  teeth  and  the  bones  of  the  lower  surface  show  that  the  two  forms 
can  not  be  placed  in  the  same  genus,  and  render  it  doubtful  whether  they  should  be 
placed  in  the  same  family.  A  comparison  with  Branson's  figures1  shows  that  the  skull 
was  a  little  broader,  proportionately,  than  in  Anaschisma  and  that  the  orbits  were  a 
little  farther  forward.  Branson  was  unable  to  trace  all  the  sutures  on  the  upper  surface 
of  his  specimen,  but,  so  far  as  he  was  able  to  determine  them,  the  position  and  relations 
of  the  bones  correspond  as  well  as  could  be  expected  in  animals  in  which  there  was  so 
much  of  individual  variation.  A  comparison  of  his  figures  with  figure  1,  A  and  B,  of 
t  his  paper  will  show  the  position  of  the  sutures  he  was  unable  to  follow,  outlining  in  whole 
or  in  part  the  lachrymals,  the  quadratojugals,  the  jugals,  and  the  maxillaries.  In 
Buettneria  the  lachrymals  are  small  elements  not  reaching  to  the  nares;  the  maxillaries 
extend  inward  anterior  to  the  orbits  and  form  a  part  of  the  posterior  and  lateral  bound- 
aries of  the  nares;  posteriorly  they  lie  upon  the  sides  of  the  skull,  and  the  postorbital 
portions  are  only  visible  from  above  as  narrow  bands.  The  premaxillaries,  nasals, 
frontals,  and  parietals  exhibit  a  decided  asymmetry.  In  both  the  figures  and  the  plates 
it  will  be  seen  that  the  extremities  of  the  tabulare  have  been  restored;  it  may  easily 
be  that  these  have  been  made  too  large,  as  the  projections  are  very  slight  in  Anaschisma. 

Not  only  the  sutures  but  the  slime-canals  are  very  perfectly  shown  in  the  specimen. 
(See  fig.  1  A.  The  course  of  the  sutures  and  the  canals  shown  in  the  figures  was  traced 
with  a  camera  lucida  and  the  lines  are  almost  exactly  as  they  appear  in  the  specimen; 
the  figures  have  not  been  diagrammatized  to  any  extent.  The  edges  of  the  slime-canals 
have  been  traced  as  straight  lines  to  distinguish  them  from  the  sutures.)  The  course 
of  the  slime-canals  is  similar  to  that  in  Anaschisma,  but  differs  in  one  or  two  important 
particulars.  Adopting  the  nomenclature  proposed  by  Moodie,2  the  anterior  com- 
missure and  the  occipital  cross-commissure  are  absent;  the  course  of  the  supraorbital 
canals  between  the  orbits  and  nares  is  quite  different  (compare  fig.  14  of  Moodie's  paper). 

1  Branson,  E.  B.,  Journal  of  Geology,  vol.  xm,  figs.  1  and  7,  1905. 

2  Moodie,  R.  L.,  Journal  of  Morphology,  vol.  xix,  No.  2,  p.  513,  1908. 


14 


NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 


The  infraorbital  canal  turns  sharply  inward  across  the  short  lachrymal  bone  and  joins 
the  supraorbital;  the  single  canal  thus  formed  runs  forward  for  a  short  distance  and  then 
bifurcates  on  the  anterior  part  of  the  maxillary  just  posterior  to  the  narial  opening. 
The  outer  branch  runs  forward  for  a  short  distance  and  terminates  in  an  irregular  expan- 
sion. The  inner  branch  follows  the  normal  course  of  the  supraorbital  canal;  there  is  no 
antorbital  commissure.  Posterior  to  the  orbit  the  supraorbital  canal  is  complete  and 
runs  backward  to  join  the  temporal  canal.  It  will  be  observed  that  the  supraorbital 
canal  on  the  left  side  lies  for  a  short  distance  on  the  frontal;  on  the  right  side  it  does  not 


pmx 


B 


pmx 


FKI.   1. — Buettneria  perfecta,  skull  of,  No'.  7475,  University  of  Michigan. 

A.  Upper  surface.  B.  Lower  surface. 

C.  Posterior  surface.  D.  Lateral  surface. 

pmx.,  premaxillary;  mx.,  maxillary;  n.,  nasal;  pf.,  prefrontal;  /.,  frontal;  I.,  lachrymal;  pto.,  post- 
orbital;  plf.,  postf rental ;  j.,jugal;  s(.,supratemporal;  p.,  parietal;  sq.,  squamosal;  qj., 
quadratojugal;  tab.,  tabulare;  dso.,  dermsupraoccipital;  eo.,  exoccipital;  vo.,  vomer; 
ps.,  parasphenoid;  trf,  transverse;  pal.,  palatine;  q.,  quadrate;  xl,  outlet  for  eleventh 
nerve;  a.pt.,  anterior  rising  process  of  pterygoid;  p.pt.,  posterior  rising  process  of  ptcry- 
goid;  qf.,  quadrate  foramen;  o.,  orbit. 

touch  that  element.  The  supraorbital  and  the  temporal  canals  meet  at  a  sharp  angle, 
and  there  is  a  canal  connecting  them  with  the  infraorbital.  Continuing  backward,  the 
temporal  canals  lie  upon  the  supratemporal  bones  and  turn  sharply  outward  at  their 
posterior  ends;  on  the  left  side  the  canal  touches  the  anterior  outer  corner  of  the  tabulare; 
on  the  right  side  it  clears  that  bone.  The  jugal  canal  continues  backward  to  the  ex- 
tremity of  the  quadratojugal  and,  with  a  slight  interruption,  turns  inward  for  a  short 
distance  near  the  posterior  edge  of  the  squamosal. 

The  edges  of  the  canals  are  irregular  and  the  sculpture  is  continued  on  the  bottom 
of  the  grooves.  It  is  evident  that  in  this  specimen  there  is  a  departure  from  the  usual 
and  (according  to  Moodie)  morphologically  important  position  of  the  canals;  that  is, 


THE   UPPER   TKIASSIC   OF   WESTERN   TEXAS.  15 

they  do  not  lie  upon  definite  bones  so  certainly  as  to  be  entirely  dependable  criteria  for 
the  determination  of  the  homology  of  the  bones  with  those  of  the  fish  skull.  This  is 
particularly  noticeable  in  the  posterior  part  of  the  course  of  the  temporal  canals  and  their 
relation  to  the  tabulare.  In  comparison  with  the  course  of  the  canals  in  Meloposaurus, 
as  given  by  Moodie,  the  differences  are  quite  similar  to  those  noted  in  comparison  with 
Anaschisma. 

The  lower  surface  of  the  skull. — In  this  region  the  skull  shows  very  decided  differences 
from  Anaschisma.  Branson  states  that  in  Anaschisma  each  palatine  bone  bears  only  a 
single  tooth,  and  this  has  been  confirmed  by  a  reexamination  of  the  skull  by  Mr.  Paul 
Miller.  It  is  also  stated  by  Branson  that  there  are  four  teeth  on  the  anterior  edge  of 
each  prevomer  (vomer),  but  no  mention  is  made  of  a  row  of  teeth  on  the  inner  edges  of 
the  narial  openings.  It  may  be  that  these  rows  are  obscured  by  the  condition  of  the 
specimen  in  the  University  of  Chicago.  The  vomers  are  shown  in  Anaschisma  as  ter- 
minating behind  in  long  points  which  extend  down  the  side  of  the  parasphenoid.  The 
transverse  bones  are  shown  as  large  elements.  The  character  of  the  articulation  of  the 
parasphenoids  with  the  exoccipitals  is  very  different  in  the  two  forms.  Mr.  Miller  has 
reexamined  this  region  and  assures  the  author  that  there  is  a  median  suture  as  shown  by 
Branson  and  interpreted  by  him  as  the  meeting  of  the  exoccipitals  and  that  there  is  a 
large  union  of  the  parasphenoid  with  the  pterygoids.  The  parasphenoid-exoccipital 
suture  is  reported  as  uncertain,  but  it  could  not  be  far  from  the  position  given  it  by  Bran- 
son. The  long  median  suture  shown  by  Branson  is  one  of  the  most  interesting  points 
about  the  skull  of  Anaschisma;  if  it  is  formed  by  the  meeting  of  the  exoccipitals  for  any 
considerable  distance  (the  posterior  portion  of  the  skull  is  restored  in  plaster),  it  is 
unique  among  the  Stegocephalia,  for  in  no  other  form  is  there  a  meeting  of  the  posterior 
ends  of  the  exoccipitals  for  any  considerable  distance,  if  at  all. 

In  Buettneria  the  premaxillaries  are  short,  with  large  openings  through  which  a 
small  part  of  the  external  nares  can  be  seen  from  below.  At  the  point  of  the  union  of 
the  premaxillaries  with  the  vomers  there  is  a  small  irregular  depression  in  the  median 
line  which  may  be  significant  or  may  be  due  only  to  imperfect  ossification  at  the  meeting- 
point  of  the  four  bones.  There  are  13-13  teeth  on  the  premaxillaries. 

The  vomers  are  large  flat  plates;  the  anterior  outer  part  forms  the  floor  of  the  external 
narial  opening  when  seen  directly  from  above.  The  anterior  outer  corners  support  large 
tusks  on  each  side;  these  were  placed  in  pairs  in  which  the  tusks  were  alternately  func- 
tional; on  the  left  side  the  anterior  one  was  in  use  and  on  the  right  the  posterior  one 
at  the  time  of  the  death  of  the  animal.  On  the  anterior  edges  of  the  bones  between 
the  tusks  there  is  a  nearly  straight  row  of  fairly  large  teeth.  There  are  5  teeth  on  each 
side,  the  outer  one  smaller  than  the  others.  On  the  inner  edge  of  the  internal  narial 
openings  there  is  a  row  of  small  teeth,  18  to  20  in  number;  the  rows  terminate  posteriorly 
at  the  palatine-vomer  suture;  anteriorly  they  are  separated  from  the  tusks  by  a  short 
vacant  space.  Within  the  inner  edge  of  the  internal  nares  there  is  a  small  cluster  of 
very  small  teeth;  these  point  toward  the  center  of  the  opening  in  the  specimen. 

The  palatines  are  separated  from  the  maxillaries  by  a  long,  straight  suture,  and  from 
the  premaxillaries  and  the  vomers  by  clearly  defined  sutures,  as  shown  in  figure  1  B, 
and  plate  1,  fig.  B.  External  to  the  posterior  half  of  the  internal  nares  there  are  large 
paired  tusks;  as  in  the  vomerine  tusks,  the  functional  teeth  of  the  pairs  are  alternate  in 
position.  Just  posterior  to  the  internal  nares  is  a  small  cluster  of  irregular  teeth.  5  to  6 
in  number.  The  long  row  of  teeth  on  the  outer  edge  begins  just  posterior  to  the  tusks  and 
is  continuous  to  the  extreme  posterior  end.  The  teeth  are  very  closely  set  and  diminish 
to  exceedingly  small  size  towards  the  rear;  many  of  the  teeth  are  represented  by  empty 
spaces  and  were  apparently  not  functional  at  the  time  of  death.  There  are  36  to  38 
teeth  on  each  side.  The  palatine  joins  the  pterygoid  by  an  oblique  suture. 


16  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

The  transverse  bone,  if  present,  is  a  small  element.  On  each  side  there  is  an  uncer- 
tain line,  indicated  in  figure  1  B,  which  seems  to  mark  the  separation  of  a  distinct  element 
from  the  pterygoid.  On  the  right  side  the  small  element  is  slightly  displaced,  indicating 
its  distinct  character. 

The  maxillaries  appear  on  the  lower  surface  as  a  tooth-bearing  edge  only.  There 
are  no  tusks.  The  bone  of  the  right  side,  which  is  complete,  carries  97  teeth  and  spaces; 
allowing  for  the  small  part  missing  on  the  left  side  there  would  be  98  on  that  side.  These 
numbers  were  certainly  not  a  fixed  quantity  in  the  individual  or  species. 

The  parasphenoid  has  a  broad,  flat  processus  cultriformis,  which  terminates  at 
the  anterior  end  in  a  sharp  point  extending  far  forward  between  the  vomers.  In  the 
specimen  the  anterior  end  is  raised,  so  that  there  is  a  decided  elongate  pit  on  the  roof  of 
the  mouth.  This  seems  to  be  entirely  natural,  but  may  be  due,  in  part,  to  slight  post- 
mortem changes.  The  posterior  end  is  moderately  expanded  and  meets  the  pterygoids 
in  long,  clearly  marked  sutures.  The  central  part  of  this  expanded  portion  is  marked 
by  low  but  distinct  rugosities.  Near  the  posterior  end  there  is  a  low  elevation  on  each 
side,  which  runs  from  the  pterygoids  out  upon  the  parasphenoid  and  then  turns  sharply 
to  the  rear  near  the  median  line.  The  sutures  with  the  exoccipital  run  obliquely  back- 
ward and  inward  and  almost,  but  not  quite,  meet  at  the  bottom  of  the  notch  between 
the  exoccipitals.  These  sutures  are  very  complex  and  sharply  and  finely  interdigitating. 

No  trace  of  a  basioccipital  or  basisphenoid  could  be  made  out  on  the  specimen,  on 
either  the  upper  or  the  lower  side  of  the  floor  of  the  brain- case,  or  by  a  careful  examination 
of  the  edges  of  broken  pieces  in  the  process  of  preparation. 

The  pterygoids. — There  are  two  strong  rami  of  the  pterygoids  visible  on  the  lower 
surface.  The  anterior  runs  forward  and  outward  to  join  the  palatines  and  the  trans- 
verse (?)  or  maxillary.  There  is  a  slight  median  depression  on  this  ramus,  and  near 
the  anterior  end  there  is  a  small  prominence  extending  slightly  downward  and  outward. 
The  second  ramus  runs  directly  outward  to  the  quadrate;  its  lower  surface  is  rounded. 

The  quadrates. — The  articular  surface  is  concave  from  side  to  side  and  convex  in  its 
longest  diameter,  which  runs  obliquely  from  without,  inward  and  forward.  The  inner 
and  outer  edges  are  raised  into  slender,  sharp  ridges.  The  suture  between  the  quadrate 
and  the  quadratojugal  is  not  clearly  marked,  but  it  was  evidently  at  the  extremity  of  a 
process  extending  inward  from  the  quadratojugal.  Anteriorly  the  quadrate  sends  a 
process  forward  and  inward  on  the  anterior  face  of  the  anterior  rising  process  of  the 
pterygoid.  Posteriorly  the  quadrate  is  overlapped  by  the  conjoined  outer  ends  of  the 
rising  processes  of  the  pterygoid.  Between  the  quadrate  and  the  quadratojugal  there 
is  a  relatively  large  quadrate  foramen.  As  shown  in  figure  2  B,  there  is  apparently 
a  small,  distinct  element  present  between  the  anterior  rising  process  of  the  pterygoid 
and  the  inner  process  of  the  quadrate.  This  may  be  a  deceptive  appearance,  but  it  is 
present  on  both  sides  and  the  lines  between  the  elements  are  distinct  and  filled  with 
matrix.  Its  meaning  is  unknown;  certainly  it  is  not  a  part  of  a  descending  process  from 
the  skull-roof,  as  the  lower  side  of  the  roofing  bones  at  this  point  is  perfectly  smooth. 

The  exoccipitals  carry  the  large,  distinct  condyles,  which  are  separated  by  a  deep 
notch  extending  forward  to  the  parasphenoid  bone.  There  is  a  good-sized  foramen  on 
the  lower  side  of  each,  which  probably  transmitted  the  X  and  XI  nerves  and  the  jugular 
vein.  On  the  middle  of  the  outer  side  is  the  foramen  for  the  XII  (?)  nerve.  At  the 
base  of  the  rising  process  which  articulates  with  the  dermsupraoccipital  and  the  tabulare 
there  is  a  large  foramen  on  the  inner  side  which  transmitted  the  X  nerve. 

The  posterior  Jace  oj  the  skull  (fig.  1  c,  and  plate  2,  fig.  A).— The  dermsupraoccipitals 
are  visible  in  the  median  line  and  are  separated  by  a  distinct  suture.  They  join  the 
tabulare  by  straight  vertical  sutures.  The  space  between  the  dermsupraoccipitals  was 
filled  in  large  part  by  a  mass  of  cartilage  in  the  absence  of  a  supraoccipital. 


CASE 


PLATE  2 


A.  Posterior  surface  (if  skull  of  HuHliun'a  perfecta.      X0.3. 

B.  Enlarged  view  of  portion  of  the  palatine  and  maxillary  of  same,  showing  the 

teeth    opposite    the  internal  nares.     The    labyrinthine    structure    is 
clearly  seen.     X2. 

C.  Metoposaunu(f)  jonesi,  No.  3814,  U.  of  Mich.     X0.3.     Ventral  surface  of 

clavicles  and  interrlaviclcs. 


THE   UPPER   TEIASSIC    OF   WESTERN   TEXAS.  17 

The  exoccipilals  meet  the  tabulare  and  the  dermsupraoccipitals  by  strong,  finely 
interdigitating  sutures.  On  the  left  side  there  is  preserved  a  portion  of  a  thin  process 
extending  inward,  which,  with  its  fellow  of  the  opposite  side,  forms  a  more  or  less  com- 
plete shelf  dividing  the  foramen  magnum  from  the  space  left  by  the  disappearance  of 
the  supraoccipital  cartilage.  The  articular  surfaces  of  the  condyles  face  backward  and 
inward. 

On  either  side  of  the  exoccipitals  the  posterior  rising  processes  of  the  pterygoids 
extend  outward  to  the  quadrates.  The  processes  rise  toward  the  upper  edge  of  the 
squamosal,  but  do  not  reach  to  it  in  the  specimen,  ending  in  a  thin  and  broken  edge  on 
both  sides.  Anterior  to  this  process  the  posterior  face  of  the  anterior  rising  process 
may  be  seen  through  the  great  otic  vacuity.  Between  the  two  rising  processes  is  received 
the  descending  process  of  the  squamosal.  The  otic  vacuity  lies  between  the  exoccipital, 
the  tabulare,  the  squamosal,  and  the  posterior  rising  process  of  the  pterygoid  (fig.  1  c). 

The  quadrate  foramen  is  relatively  larger  than  in  Anaschisma.1 

The  ophisthotic  is  completely  covered  by  the  descending  process  of  the  dermsupraoc- 
cipital  and  the  tabulare.  The  general  similarity  between  the  posterior  surfaces  of  the 
skulls  in  the  two  forms,  Anaschisma  and  Buettneria,  is  obvious  from  a  comparison  of  the 
figures,  but  it  is  equally  obvious  that  there  is  one  great  difference:  in  the  latter  form 
there  are  no  post-temporal  fenestrse;  the  place  of  each  fenestra  is  taken  by  a  deep  pit 
with  an  imperf orate  bottom.  The  resemblance  is  even  greater  to  Metoposaurus  diag- 
nosticus  as  figured  by  Watson.2  It  is  probable  that  the  part  which  he  has  called  the 
epipterygoid  (E.  Pt.  ?)  is  a  part  of  the  descending  process  of  the  squamosal.  In  corre- 
spondence, Doctor  Watson  suggests  that  the  space  between  the  two  ascending  processes 
of  the  pterygoid  was  filled  with  a  "persistent  pterygo-quadrate  cartilage  that  is  essen- 
tially an  epipterygoid,"  and  suggests  that  the  part  described  in  this  paper  is  an  ossifica- 
tion of  that  cartilage;  but  it  is  clearly  a  process  from  the  squamosal,  as  the  broken  edges 
in  the  specimen  were  clean  and  fitted  perfectly.  His  figure  shows  but  a  slight  develop- 
ment of  the  posterior  rising  process  of  the  pterygoid,  which  in  Anaschisma  and  Bueltneria 
reaches  nearly  to  the  upper  edge  of  the  squamosal.  In  the  place  of  a  large  post-temporal 
fenestra  he  shows  a  small  foramen  on  the  dermsupraoccipital-tabulare  suture,  a  condition 
approaching  very  closely  to  that  found  in  Buettneria. 

The  upper  (inner)  surface  of  the  basicranial  bones. — The  condition  of  the  specimen 
was  such  that  it  was  possible  to  remove  the  matrix  completely  from  the  brain-case  and 
the  inner  side  of  all  the  bones,  leaving  them  as  clean  and  intelligible  as  the  outer  side 
(fig.  2  A). 

The  anterior  portion  of  the  parasphenoid  is  marked  by  a  deep,  flat-bottomed  groove 
with  thin,  abrupt  borders;  opposite  the  anterior  edges  of  the  palatine  vacuities  this 
groove  is  nearly  equal  to  the  width  of  the  bone  (23  mm.),  but  it  contracts  gradually  and 
regularly  to  the  rear,  and  opposite  the  posterior  edges  of  the  palatine  vacuities  it  is 
not  more  than  5  mm.  in  breadth;  at  the  same  time  the  groove  becomes  much  shallower, 
due  to  the  gradual  thickening  of  the  bone.  The  edges  become  more  rounded  and  lower 
as  they  thicken  to  the  rear,  and  finally  disappear  about  opposite  to  the  center  of  the 
broad  posterior  portion  of  the  parasphenoid.  On  either  side  of  the  center  of  ossification 
and  a  little  to  the  rear  there  are  openings  which  extend  obliquely  outward  and  backward 
and  are  inclosed  by  a  low  arch  of  bone,  so  that  they  do  not  lie  within  the  substance  of 
the  parasphenoid,  but  rather  upon  its  surface,  covered  by  the  arch.  The  outer  end  of 
the  arch  is  slightly  wider  than  the  inner  and  terminates  in  an  irregular  edge,  as  if  it  had 
been  covered  with  cartilage  during  life.  The  length  of  the  arch  is  32  mm.  The  meaning 

1  Branson,  E.  B  ,  Journal  of  Geology,  vol.  xm,  Xo.  7,  fig.  3,  1905. 

-  Watson,  D.  M.  S.,  Transactions  Royal  Society  of  London,  vol.  209,  Series  B,  fig.  10,  1919. 


18  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

of  these  peculiar  structures  is  not  certain;  a  careful  study  of  both  the  upper  and  lower 
surfaces  and  the  broken  edges  revealed  no  indication  of  separate  basioccipital  or  basi- 
sphenoid  ossification.  It  is  probable  that  the  basisphenoid  cartilage  became  much  reduced 
and  the  internal  carotid  arteries  were  forced  down  upon  the  parasphenoid  and  passed 
for  a  short  distance  through  the  arches.  This  suggestion  is  supported  by  the  position 
of  the  arches  and  the  fact  that  the  internal  carotid  arteries  entered  the  brain-case  through 
the  posterior  part  of  the  palatine  vacuities  and  then  turned  backward.  Watson1 
identified  markings  in  the  specimen  of  Laccocephalus  in  this  position  as  the  grooves  of 
the  internal  carotids,  though  he  interpreted  the  method  of  the  arterial  entrance  into  the 
skull  in  a  different  manner.  On  the  surface  of  each  arch,  nearer  to  the  inner  than  the 
outer  end,  there  is  a  small  foramen  penetrating  through  the  wall  to  the  canal  below. 
Just  anterior  to  the  inner  ends  of  the  arches  there  are  slightly  elongated  rugosities; 
these  are  in  the  direct  line  of  the  continuation  of  the  ridges  on  the  upper  side  of  the 
parasphenoid  and  of  the  ridges  on  the  inner  edges  of  the  pterygoids.  Anterior  to  these 
rugosities  there  are  small  foramina  entering  the  skull  from  before  backward;  they  are 
probably  no  more  than  openings  for  nutrient  vessels.  The  sutures  between  the  para- 
sphenoid and  the  pterygoids  can  be  easily  traced;  they  run  irregularly  backward  from  a 
point  at  the  center  of  the  posterior  edges  of  the  palatine  vacuities  and  pass  beneath  the 
outer  edges  of  the  arches  just  described,  i.  e.,  the  arches  are  entirely  upon  the  parasphe- 
noid. Posterior  to  the  arches  the  sutures  appear  again  and  continue  backward,  convex 
outwardly,  and  then  converge  to  end  very  close  together  at  the  base  of  the  deep  notch 
between  the  exoccipitals. 

The  pterygoids. — -The  upper  face  of  the  anterior  ramus  of  the  pterygoid  is  marked 
by  a  wide,  shallow  groove  which  becomes  more  distinct  posteriorly  to  a  point  about 
opposite  the  posterior  edge  of  the  palatine  vacuity;  the  outer  edge  of  the  groove  is  distinct 
for  its  whole  length,  but  the  inner  becomes  definite  only  in  its  posterior  portion.  The 
outer  edge  of  the  ramus  is  raised  into  a  slight  prominence  just  at  the  origin  of  the  anterior 
rising  process  of  the  quadrate  ramus  of  the  pterygoid.  The  pterygoid  joins  the  para- 
sphenoid, as  is  indicated  in  figure  1  B,  and  connects  with  the  exoccipital  just  posterior  to 
the  origin  of  the  quadrate  ramus.  Just  anterior  to  the  junction  of  the  pterygoid  and  the 
exoccipital  there  is  a  foramen  near  the  inner  edge  of  the  pterygoid;  on  the  left  side  the 
bone  is  broken  around  the  foramen  and  shows  that  it  enters  into  a  considerable  cavity 
in  the  body  of  the  bone. 

The  upper  surface  of  the  quadrate  ramus  is  most  interesting.  The  perfection  of 
the  structures  preserved  has  rendered  it  a  little  difficult  to  reconcile  the  conditions  found 
with  the  descriptions  of  less  perfect  specimens,  but,  in  the  light  cast  by  the  study  of  this 
specimen,  the  previous  descriptions  can  be  brought  into  more  or  less  harmony.  There 
are  two  distinct  rising  processes,  an  anterior  and  a  posterior  (see  figs.  2  A  and  2  B).  These 
are  directly  continuous  with  the  body  of  the  bone  and  extend  for  nearly  the  full  length 
of  the  ramus;  there  is  no  trace  of  a  suture  in  the  specimen,  where  every  suture  is  revealed 
with  almost  diagrammatic  clarity.  The  processes  are  inclined  backward  as  they  rise 
and  are  separated  by  a  considerable  space  at  their  inner  ends,  but  are  very  closely  approxi- 
mated, if  not  actually  united,  at  their  outer  ends.  The  anterior  process  rises  to  the  roof 
of  the  skull;  its  upper  edge  was  thin,  with  the  inner  half  attached  to  the  lower  surface 
of  the  parietal  and  squamosal  by  cartilage;  this  is  demonstrated  by  the  thinning  and 
irregularity  of  the  upper  edge,  by  the  line  of  low  rugosities  on  the  roof-bones  mentioned, 
and  by  the  fact  that  the  bones  were  found  in  this  position  with  a  thin  line  of  matrix 
between  them  (fig.  2  B). 

1  Watson,  D.  M.  S.,  Transactions  Philosophical  Society  of  London,  vol.  209,  Series  B,  pi.  2,  1919. 


TIIK    II'I'EH   TRIASSIC    OF   WESTERN   TEXAS. 


19 


The  inner  end  of  the  anterior  process  rises  from  a  triangular  base.  From  the 
center  of  the  posterior  end  of  the  groove  on  the  palatine  rainus  of  the  pterygoid  a  thin 
wall  rises  obliquely  backward;  beneath  this  there  is  a  deep  pit,  with  its  mouth  just 
anterior  to  the  outer  end  of  the  arch  described  on  the  parasphenoid.  This  pit  extends 
obliquely  backward  and  its  apex  is  perforated  by  two  small  foramina  on  the  left,  side; 
the  pit  on  the  right  side  is  perforated  by  a  single  foramen.  Posterior  to  this  pit  the 
base  of  the  process  is  thickened  (fig. 2  B)  just  opposite  the  anterior  edge  of  the  outer 


FIG.  2. — •Buettneria  perfecta. 

A.  Upper  (inner)  view  of  the  bones 

of  the  hasicranial  region. 
d.sq.,  descending  process  of 
the  squamosal;  i.e.,  open- 
ing of  cavity  for  the  inter- 
nal carotid  artery;  x. 
outlet  for  the  tenth  cranial 
nerve.  Other  lettering  as 
in  figure  1. 

B.  Upper  view  of  the  left  quadrate 

ramus  of  the  pterygoid. 
Lettering  as  in  previous 
figures. 


opening  of  the  arch  on  the  parasphenoid ;  beneath  it  a  second  pit  passes  forward  and 
slightly  inward  and  is  imperforate.  The  apices  of  the  two  pits  are  separated  by  a 
thin  wall.  The  third  part  of  the  triangular  base  is  formed  by  the  lower  part  of  the  anterior 
rising  process.  The  upper  part  of  this  rising  process  is  somewhat  crumpled;  it  is  impos- 
sible to  interpret  the  appearance  exactly,  for  the  distortion  gives  the  appearance  of 
reduplication,  as  if  the  bone  were  made  up  of  superimposed  laminae  or,  which  seems  very 
improbable,  of  separate  thin  bones. 

On  the  posterior  edge  of  the  quadrate  ramus  is  the  posterior  rising  process.  Its 
inner  end  originates  just  posterior  and  external  to  the  second  pit  described  above;  it 
reaches  nearly  as  great  a  height  as  the  anterior  one,  but  there  is  no  indication  that  it 
WHS  ever  attached  to  the  roof  above;  in  the  specimen  there  is  quite  a  space  between  the 
two.  This  process  is  shown  by  Quenstedt1  as  reaching  up  to  the  squamosal  in  Cydo- 
tosaurus  (Mastodonsaurus)  robustus.  Fraas,2  however,  shows  the  plate  of  much  less 
height  in  Cyclolosaurus  posthumus.  Watson,  in  his  figure  after  Fraas,  draws  it  much 
higher.3 

The  outer  ends  of  the  two  processes  unite  apparently  without  suture  and  clasp  the 
inner  and  part  of  the  posterior  face  of  the  quadrate.  Into  the  deep  cleft  between  the 
two  processes  descends  the  process  from  the  squamosal.  The  relations  of  these  processes 

1  Quenstedt.  !•'.  A..  Die  M;i-toil<m>;uirier  iiu  granc-n  KeupersaiuLstoine  Wurtemlxjrg'ssind  Batrachier,  Tubingen, 

1850,  pi.  3,  fig.  10. 
*  Fraas,  E.,  Neue  Labyrinthodonten  aus  der  Schwabischen  Trias,  Paleontographica,  Bd.  LX,  p!.  xvin,  fig.  2, 

1913. 
» Watson,  D.  M.  8.,  loc.  cit.,  fig.  30  c,  p.  54. 


20  NEW   EEPTILES   AND    STEGOCEPHALIANS   FROM 

is  very  puzzling  in  places;  towards  the  outer  ends  the  three  seem  to  be  indistinguishably 
fused;  this  may  be  natural  or  may  be  due  to  the  very  close  approximation  of  the  elements, 
partly  due  to  a  very  slight  compression  in  fossilization.  It  is  possible  that  the  descending 
process  was  surrounded  by  cartilage  and  that  the  partial  ossification  of  this  cartilage 
may  have  produced  the  appearance  of  fusion  of  the  bones.  The  thin  outer  edge  formed 
by  the  united  or  approximated  ends  of  the  processes  descends  obliquely  forward  and 
disappears  behind  the  quadrate;  there  is  a  small  foramen  between  the  bones  at  this  point. 

The  quadrate. — The  upper  surface  of  the  quadrate  was  seen  in  the  specimen  during 
preparation;  it  sends  a  shorter  and  heavier  process  backward  and  inward  to  articulate 
with  the  posterior  process  of  the  pterygoid,  and  a  longer  and  more  slender  process  for- 
ward which  lies  on  the  anterior  face  of  the  anterior  process  of  the  pterygoid.  This 
anterior  process  is  expanded  vertically  and  in  life  was  either  applied  closely  to  the 
pterygoid  or  attached  to  it  loosely  by  cartilage.  In  the  specimen  it  is  separated  from 
the  pterygoid  on  both  sides  by  a  space  of  a  millimeter  or  two,  now  filled  with  matrix. 

The  exoccipitals. — These  join  the  pterygoids  and  the  parasphenoids  by  finely  inter- 
digitating  sutures.  The  edges  of  the  parts  of  the  exoccipitals,  which  form  the  walls  of  the 
brain-case,  are  broken  away,  but  they  did  not  rise  to  and  connect  with  the  roof,  as  is 
proven  by  the  absolutely  smooth  surface  of  the  under  side  of  the  roof-bones.  Anterior 
to  the  rising  process  there  is  a  foramen;  a  little  farther  forward  and  somewhat  laterally 
there  are  two  small  foramina  on  the  left  side  and  a  single  foramen  on  the  right  side.  At 
the  base  of  the  rising  process  on  the  posterior  outer  angle  there  is  a  small  foramen.  On 
the  right  side  there  is  a  second  foramen  on  the  posterior  inner  corner,  but  this  is  lacking 
on  the  left  side. 

The  lower  surface  of  the  roof  of  the  cranial  area  (fig.  3). — -The  dermsupraoccipitals 
and  the  tabulare  send  down  processes  which  unite  with  the  rising  processes  of  the  exoc- 
cipitals. On  the  inner  side  of  these  processes  there  is  a  thin  plate  of  bone,  evidently 
the  very  rudimentary  opisthotic.  On  each  dermsupraoccipital  there  is  a  small,  elongate 
area  with  a  rough  surface  and  slightly  raised  edges;  that  of  the  left  side  reaches  to  and 
even  crosses  the  dermsupraoccipital-squamosal  suture;  that  of  the  right  side  is  shorter. 
These  are  evidently  points  of  cartilaginous  attachment  for  some  element  of  the  brain- 
wall,  probably  the  prootic,  but  no  trace  of  such  an  element  was  preserved.  The  tabulare 
has  small  presentation  on  the  lower  surface  and  the  outline  is  nearly  square.  About 
the  center  of  the  bone  there  is  a  deep  pit  with  the  inner  edges  slightly  elevated.  These 
pits  end  blindly  and  do  not  penetrate  more  than  halfway  through  the  bone.  Outside 
of  the  pits  the  remainder  of  the  surface  is  rough  and  evidently  afforded  cartilaginous 
attachment;  the  rough  area  terminates  sharply  at  the  tabulare-squamosal  suture,  but 
the  adjacent  portions  of  the  squamosal  are  marked  with  fine  grooves,  as  if  by  a  plexus 
of  blood-vessels.  There  is  no  element  which  can  be  supposed  to  have  attached  to  this 
area,  unless  it  be  the  opisthotic,  which  has  nearly  disappeared  in  the  genus;  this  sugges- 
tion seems  the  more  unlikely,  as,  if  it  were  attached,  the  opisthotic  would  appear  on  the 
posterior  face  of  the  skull,  which  it  does  not  do  in  the  Metoposauridse.  On  the  other 
hand,  Watson1  shows  an  ascending  plate  on  the  inner  edge  of  the  exoccipital  in  Capito- 
saurus.  The  thin  plate  on  the  inner  side  of  the  rising  process  of  the  exoccipital  of 
Buettneria  may  possibly  be  such  a  process,  though  it  is  apparently  free  from  the  exoc- 
cipital and  has  been  interpreted  as  the  opisthotic.  The  meaning  of  the  large  pits  on  the 
tabulare  is  not  understood. 

Attached  to  the  inner  edge  of  the  anterior  rising  process  of  the  pterygoid  there  was 
found,  on  the  left  side,  a  small  plate  of  bone,  somewhat  constricted  in  the  middle.  This 
lay  vertically  in  the  matrix  and  extended  horizontally  inward,  across  the  posterior  end 

1  Watson,  D.  M.  S.,  loc.  cit.,  fig.  11  A. 


THE    UPPER   TRIASSIC    OF   WESTERN   TEXAS. 


21 


of  the  groove  on  the  upper  face  of  the  posterior  end  of  the  pterygoid.  It  is  perhaps  an 
ossification  of  the  alispenoid  or  orbitosphenoid  cartilage;  no  corresponding  element  was 
found  on  the  other  side. 

One  of  the  remarkable  features  of  the  skull  is  the  evidently  large  amount  of  cartilage 
in  the  walls  of  the  brain-case.  The  stapes  were  lost  and  the  otic  opening  is  very  large, 
the  bones  around  it  terminating  in  smooth  edges.  There  seems  no  escape  from  the 
conclusion  that  the  whole  of  the  area  of  the  organ  of  hearing  was  cartilaginous.  The 
whole  of  the  lower  surface  of  the  bones  in  the  area  occupied  by  the  brain  is  perfectly 
smooth,  with  the  exceptions  noted.  There  was  no  attachment  of  exoccipital,  epiotic, 
or  opisthotic  to  the  upper  wall,  and  the  same  condition  in  front  shows  that  there 
was  no  ossification  of  the  ethmoidal  elements. 


FIG.  3. — Buettneria  perfecta. 

View  of  lower  surface  of  roof-bones  of  cranial 
region. 

x',  rugosity  showing  place  of  attachment  of 
the  prootic;  x,  rugosity  showing 
place  of  attachment  of  the  anterior 
rising  process  of  the  pterygoid; 
op?,  opisthotic.  Other  lettering  as 
in  figure  1. 


op? 


Off 


The  teeth  are  imperfect,  the  tops  having  been  broken  away  and  the  stubs  worn 
as  the  skull  was  dragged,  palatal  side  down,  over  the  bottom.  In  even  the  smaller 
teeth  the  broken  surfaces  show  the  labyrinthine  structure  (plate  2  B). 

It  is  evident  that  this  genus  has  its  nearest  relations  in  Metoposaurus  and  belongs 
in  the  family  Metoposauridse  of  Watson,1  but  it  is  very  doubtful  whether  Anaschisma 
can  be  retained  in  the  same  family.  From  Metoposaurus  the  genus  Buettneria  differs  in 
the  narrower  processus  culiriformis  and  the  shape  of  the  posterior  portion  of  the  para- 
sphenoid,  in  the  smaller  (or  absent)  transverse,  in  the  shorter  quadrate  ramus  of  the 
pterygoid,  in  the  loss  of  all  trace  of  the  post-temporal  foramina,  in  the  presence  of  a 
series  of  small  teeth  on  the  internal  nares,  etc. 

Measurements.— Total  length  of  skull,  443.2  mm.  Breadth  of  skull  at  posterior 
end,  344.2  mm. 

For  this  new  form  I  take  great  pleasure  in  proposing  the  name  Buettneria  perfecta, 
in  recognition  of  the  interest,  patience,  and  skill  of  Mr.  William  H.  Buettner,  who  has 
prepared  the  skull  and  mounted  it  in  all  of  its  perfection. 

A  second  skull  of  the  same  genus,  but  far  less  perfect,  showing  only  the  upper 
surface,  was  found  in  the  same  region.  Many  other  isolated  bones  were  found,  indicating 

1  Watson,  D.  M.  8.,  loo.  at.,  p.  07.  Sec  also  v.  Hucnc,  Gonioglyptus,  ein  ulttria-sichi-r  sicgorcplial.-  an.>  Indien, 
Acta  Zoologica,  p.  456,  1920.  In  this  paper  v.  Huene  arrived,  independently,  at  almost  exactly  the  same 
arrangement  of  the  families  of  the  Stegocephalia  as  did  Watson  a  year  earlier. 


22 


NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 


other  parts  of  the  skeleton,  but  of  these  the  majority  are  vertebrae  and  bones  of  the  pec- 
toral girdle;  remains  of  limb-bones  are  scarcely  represented  in  the  collection.  Some  of 
the  isolated  bones  are  described  below. 

A  nearly  perfect  left  ramus  of  a  lower  jaw,  No.  7469,  University  of  Michigan  col- 
lection, was  found  by  the  author  in  the  breaks  of  Sand  Creek,  just  south  of  Cedar  Moun- 
tain. The  jaw  lacks  the  extreme  anterior  end  and  the  posterior  end  is  somewhat  crushed, 
but  the  greater  portion  is  in  good  condition.  The  length  of  the  jaw  is,  allowing  for  the 
missing  anterior  end,  43  mm.,  somewhat  shorter  than  the  jaw  of  Busttneria  as  indicated 
by  the  skull.  The  jaw  as  preserved  shows  too  great  a  curvature  to  be  associated  with 
the  skull  in  the  same  genus.  The  jaw  is  illustrated  in  figure  4,  A  and  B.  On  the  inner 


Fia.  4. 

A.  Outer  surface  of  left  ramus  of  jaw  of  a  large 

Stegocephalian,  No.  7469,  U.  of  Mich. 
X  0.25. 

B.  Inner  surface  of  the  same  jaw  shown  in  A. 
dent.,  dentary;  cor.,  coronoid;   swr.  ang.,  suran- 

gular;  art.,  articular;  sp.,  splenial; 
pt.  sp.,  postsplenial;  ang.,  angular; 
pr.  art.,  prearticular. 


pt.sp 


side  there  is  a  relatively  large  supra-Meckalian  foramen  and  below  this  a  surprisingly 
large  lower  opening.  The  splenial  is  short  and  confined  to  the  anterior  fourth  of  the 
ramus;  it  appears  on  both  the  inner  and  the  outer  sides  of  the  lower  edge  and  evidently 
took  part  in  the  symphysis.  The  sutures  marking  the  outlines  of  this  bone  are  clear 
and  distinct.  Posterior  to  the  splenial  there  is  a  postsplenial  which  forms  the  middle 
portion  of  the  inner  surface  of  the  jaw;  it  appears  on  both  the  inner  and  outer  sides  of 
the  lower  edge,  but  on  the  inner  side  rises  in  a  smooth  plate  to  form  the  greater  part  of 
the  inner  surface.  It  is  pierced  by  two  good-sized  foramina.  The  posterior  edge  of 
the  postsplenial  extends  back  to  the  middle  of  the  lower  edge  of  the  lower  Meckalian 
opening,  where  the  suture  is  clear  and  distinct.  From  the  middle  of  the  upper  edge 
there  is  apparently  a  suture  of  irregular  outline  extending  downward,  but  it  can  be  traced 
for  only  a  short  distance;  the  exact  nature  of  this  apparent  suture  can  not  be  made  out; 
it  may  indicate  the  presence  of  an  intercoronoid  bone,  but  no  other  indications  of  either 
an  intercoronoid  or  a  precoronoid  can  be  detected.  Posterior  to  the  lower  Meckalian 
opening  the  inner  surface  of  the  bone  is  badly  crushed  and  covered  with  a  multitude  of 
small  fracture  lines  which  render  it  impossible  to  determine  the  course  of  any  sutures. 
It  is  altogether  probable  that  the  greater  part  of  this  surface  is  formed  by  the  pre- 
articular. The  anterior  edge  of  the  supra-Meckalian  opening  is  formed  by  the  coronoid 
and  the  prearticular;  it  is  probable  that  the  angular  appears  on  the  lower  edge  of  the 
inner  surface,  but  the  suture  can  not  be  made  out.  The  coronoid  extends  forward  in 
a  long  process  between  the  postsplenial  and  the  inner  edge  of  the  dentary.  The  dentary 
ends  posteriorly  in  a  sharp  process  between  the  coronoid  and  the  angular  or  surangular. 
Anteriorly  it  extends  forward,  forming  the  whole  of  the  alveolar  edge.  The  teeth  are 
small  at  the  posterior  end,  but  rapidly  increase  in  size  forward  until  they  reach  the 
maximum  size.  Under  the  binocular  microscope  the  structure  of  the  teeth  is  seen  to 
be  labyrinthine  at  the  base,  becoming  much  more  simple  near  the  apex.  No  teeth 
appear  upon  the  coronoid. 


CASE 


PLATE  3 


>0 
Ci 
O 

X 


O 

p 

«f 


PQ 


03 


I 


CO 
C5 

X 


S 


o 
P 


THE    UPPER   TRIASSIC   OF   WESTERN   TEXAS. 


23 


The  posterior  part  of  the  outer  surface  of  the  jaw  is  largely  formed  by  the  angular; 
it  is  marked  in  its  posterior  portion  by  a  very  coarse  sculpture,  which  changes  to  a 
coarse  radiating  pattern  anteriorly  and  gradually  dies  out  near  the  anterior  third  of 
the  jaw.  No  suture  can  be  made  out  between  the  angular  and  the  surangular,  and  it 
is  not  certain  that  the  surangular  appears  on  the  outer  side,  as  it  is  figured  in  Eryops 
by  Broom.  The  sutures  between  the  angular,  dentary,  postsplenial,  and  splenial  are 
all  clear  and  distinct.  Near  the  posterior  end  of  the  jaw  there  is  a  deep  linear  depression 
devoid  of  sculpture;  this  may  mark  the  position  of  the  suture  between  the  angular  and 
surangular,  but  no  traces  of  the  suture  could  be  made  out  in  or  near  the  depression. 


Fia.  5. — Outlines  of  interclavicles,  all,  except  D,  from  University  of  Michigan. 

A.  No.  7368.  B.  No.  7448.  C.  No.  3814.  D.  Metoposaurusfrassi  Lucas.  E.  No.  7266. 
F.  Posterior  portion,  No.  7367.  G.  Posterior  portion,  No.  7366.  H.  Posterior 
portion,  No.  7374. 

Viewed  from  above,  the  posterior  end  of  the  jaw  shows  two  distinct  halves  which 
seem  to  meet  as  distinct  bones  at  the  posterior  end;  these  may  be  the  angular  and  the 
surangular  or  the  surangular  and  the  prearticular.  Just  posterior  to  the  elevation  of 
the  surangular  on  the  posterior  edge  of  the  supra-Meckalian  opening  there  is  apparently 
a  distinct  element  represented  by  an  egg-like  mass  of  bone  between  the  two  separate 
halves  described  above.  This  may  be  the  articular,  as  no  other  trace  of  that  bone  can 
be  found. 

A  second  jaw  (No.  7503,  University  of  Michigan),  also  from  Sand  Creek,  is  com- 
plete, but  badly  rotted  by  gypsum.  The  sutures  can  not  be  traced,  but  the  Meckalian 


24  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

openings  are  the  same  as  in  No.  7469  and  there  is  the  same  meeting  of  two  distinct 
bones  at  the  posterior  edge  and  the  same  distinct  articular  element. 

Eight  interclavicles  were  found  in  the  same  region  as  the  skull  of  Bueltneria.  Five 
of  these  are  nearly  complete;  three  are  accompanied  by  more  or  less  complete  clavicles; 
three  are  represented  by  the  posterior  portion  only.  These  bones  are  shown  in  figure  5, 
and  plates  2  c,  3,  and  4.  It  is  evident  that  none  of  these  forms  is  specifically  identical 
with  any  of  the  described  forms  from  the  Upper  Triassic  of  Europe,  and  it  is  probable 
that  the  difference  is  of  generic  value.  Figure  6,  copied  from  Fraas,1  shows  the  char- 
acteristic form  of  the  interclavicles  in  Metoposaurus,  Cyclotosaurus,  and  Mastodonsaurus. 
In  comparing  these  with  the  interclavicles  from  the  Texas  Triassic,  it  is  evident  that 
there  is  a  great  difference  in  the  proportions;  in  the  American  forms  the  posterior  pro- 
longation is  much  less  in  relation  to  the  anterior.  In  the  specimen  previously  described 
as  Metoposaurus  jonesi,  No.  3814  of  the  University  of  Michigan  collection,  the  form 
most  closely  approaches  that  figured  by  Fraas  as  Metoposaurus  in  the  shortness  of  the 
anterior  process  and  the  breadth  as  compared  with  the  length,  but  the  posterior  process 
is  much  sharper  and  the  sculpture  is  very  different.  In  all  of  Fraas's  figures  there  is 
shown  a  strong  posterior  prolongation  of  the  clavicles  in  the  region  of  the  articulation 
with  the  shoulder  girdle,  which  is  apparently  absent  in  the  Texas  forms,  though  this  is 
not  absolutely  certain,  as  all  of  the  clavicles,  except  No.  3814,  are  imperfect  in  this 
region. 


C 


Fio.  6. — Outlines  of  interclavicles  and  clavicles. 

A.   Metoposaurus,   after  Fraas.     B.   Cydotosaurus,   after  Fraas.     C.   Mastodonsaurus, 

after  Fraas. 

The  figures  showing  the  outline  of  the  interclavicles  have  all  been  reduced  to  the 
same  scale  on  the  single  line  which  is  comparable  in  all  of  the  specimens,  i.  e.,  the 
breadth  just  at  the  posterior  edge  of  the  articular  faces  for  the  clavicles.  The  dis- 
proportion between  the  breadth  of  the  interclavicles  and  the  length  of  the  posterior 
process  posterior  to  this  line  is  sufficiently  striking  in  the  different  specimens  to  need  no 
comment.  Working  out  the  proportion  between  these  lines  in  all  of  the  specimens 
results  in  an  almost  perfect  series,  with  no  break  where  a  line  can  be  drawn  between 
groups.  The  varying  outlines  warrant  the  belief  that  there  are  several  distinct  species, 
but  upon  such  incomplete  material  the  author  does  not  feel  that  new  genera  or  even 
species  should  be  founded.  Future  discoveries  will  undoubtedly  associate  the  different 
interclavicles  with  more  characteristic  parts  of  the  skeleton;  and  if  the  differences  in 
outline  and  proportions  are  shown  to  be  more  than  developmental  or  individual  vari- 
ations, new  names  may  be  based  on  such  characters. 

1  Fraas,  E.,  Neue  Labyrinthodonten  aus  der  Scliwabischcn  Trias,  Paleontographica,  Bd.  i.x,  p.  286,  1913. 


CASE 


PLATE  4 


Buellneria  perfecta,  ventral  surfaces  of  posterior  halves  of  interclaviclcs. 
A.  No.  7367,  U.  of  Mich.     X0.34.        B.  No.  7366,  U.  of  Mich.     X0.48. 
C.  No.  7364,  U.  of  Mich.     X0.53. 


THE    UPPER   TRIASSIC   OF   WESTERN   TEXAS. 


25 


As  the  figures  are  reduced  to  the  same  scale,  it  is  necessary  to  take  the  measure- 
ments into  account  to  realize  the  difference  in  size.  The  measurements  are  given  in 
the  following  table: 


Specimen. 

1 

Total 
length. 

2 
Breadth  at 
posterior  edge  of 
face  for  clavicle. 

3 
Length  posterior 
to  line  indicated 
in  2. 

4 

Proportion 
between  2  and  3. 

No  7449   U  of  M 

mm. 
355  6 

mm. 
279  4 

mm. 
101.6 

0.36 

No.  7367,  U.  of  M  

381.0 

149.4 

.39 

No   7448   U  of  M 

381  0 

273  2 

120  8 

.44 

No.  3814,  U.  of  M  
No   7366  U  of  M 

330.2 

279.4 
254  0 

117.6 
114  4 

.45 
.45 

M.  fraasi     .        

428.8 

309.0 

150.0 

.48 

No  7368,  U.  of  M 

279  4 

172  0 

89.6 

.50 

No.  7364,  U.  of  M  

189.6 

95.4 

.50 

No.  7265,  U.  of  M 

508  4 

355.6 

225.6 

.63 

From  the  shape  of  the  interclavicles  it  is  believed  by  the  author  that  only  one 
specimen,  No.  3814,  can  be  placed  in  the  genus  Metoposaurus;  it  has  been  described  as 
M .  jonesi.1  All  but  one  of  the  others  correspond  in  a  general  way,  and  as  they  were  found 
in  the  same  region  as  the  perfect  skull  of  Buettneria  and  a  second,  imperfect  skull  of  the 
same  genus,  they  may  be  regarded,  provisionally,  as  belonging  to  that  genus.  Specimen 
No.  7364  is  decidedly  different  in  form,  proportions,  and  sculpture  and  may  be  distinct; 
the  imperfect  state  of  preservation  renders  this  somewhat  doubtful. 

The  clavicles  are  not  well  preserved,  except  in  the  specimen  No.  3814,  but  the 
general  form  and  sculpture  do  not  differ  markedly  in  the  portions  preserved.  In 
specimen  No.  7367  the  clavicles  are  long  in  correlation  with  the  long  anterior  process 
which  the  interclavicle  must  have  possessed. 

Few  other  bones  of  Stegocephalia  were  found.  A  single  humerus  of  small  size 
and  with  poorly  ossified  articular  ends  was  found  associated  with  the  small  interclavicle, 
No.  7368,  and  probably  belonged  to  the  same  individual.  Numerous  vertebral  centra 
of  typically  stereospondylus  form  were  found  scattered  in  the  beds.  One  with  a  double 
articular  face  is  undoubtedly  the  anterior  one  of  the  series.  No  neural  spines  or  other 
parts  of  the  skeleton  were  found. 


1  Case,  E.  C.,  Occasional  Papers  of  the  Museum  of  Zoology,  University  of  Michigan,  No.  82,  1920. 


26  NEW   REPTILES   AND    STEGOCEPHALIANS   PROM 

DESCRIPTION   OF  DESMATOSUCHUS   SPURENSIS   AND   THE   NEW 

SUBORDER  DESMATOSUCHIA. 

The  remains  of  this  specimen  were  found  near  the  east  bank  of  the  Blanco  or 
Catfish  River,  about  a  half  mile  east  of  the  crossing  of  the  old  mail-road  from  Spur  to 
Crosbyton,  in  Crosby  County,  Texas.  The  site  of  the  discovery  is  a  patch  of  sand  and 
sandy  clay  occupying  not  more  than  a  few  hundred  square  feet,  about  a  half  mile  north 
of  the  road.  This  patch  lies  within  a  half  mile  of  one  of  the  areas  of  exposure  of  sands, 
clays,  and  conglomerates  which  mark  the  occurrence  of  old  river-washes  at  rare  inter- 
vals, among  the  barren  clays  of  the  Upper  Triassic.  The  particular  patch  of  sand  and 
clay  in  which  the  specimen  occurred  was  evidently  accumulated  in  some  isolated  hole 
distinct  from  the  nearest  large  area  of  river  deposit.  No  other  bones  were  found  within 
half  a  mile  of  the  spot,  and  this  important  point,  bearing  upon  the  association  of  the 
bones  found  in  one  specimen,  was  checked  during  three  separate  visits  to  the  locality. 
In  working  the  specimen  out  of  the  ground  a  few  scattered  bones  were  found  in  the 
sandy  clay  of  the  upper  part  of  the  deposit,  but  the  greater  part  of  the  material  was 
found  in  single  mass  near  the  bottom,  where  the  matrix  was  a  light-colored  clay  with 
included  grains  of  sand,  abundant  traces  of  badly  decayed  vegetation,  and  lumps  of 
charcoal.  This  part  of  the  clay  was  filled  with  gypsum,  which  had  in  some  places 
badly  rotted  the  bones  and  in  other  places  formed  a  protecting  coat  which  preserved 
the  surface  in  perfect  condition.  Next  to  the  bones  there  was,  in  may  places,  a  thin 
layer  of  pyrite,  which  rendered  the  cleaning  very  difficult,  especially  the  rugose  surface 
of  the  skull.  The  pyrite  frequently  penetrated  and  filled  the  small  cavities  and 
foramina,  making  it  especially  difficult  to  work  out  some  of  the  finer  details.  Some 
parts  of  the  matrix  were  very  hard  and  colored  a  deep  black ;  when  this  sort  of  material 
was  in  contact  with  the  bone  the  preparation  was  even  more  complicated. 

It  seems  evident  that  the  remains  of  the  animal  were  washed  into  a  hole  with  a 
considerable  amount  of  vegetable  material  and  then  the  hole  was  filled  with  a  cleaner 
sand.  There  can  be  no  question  that  the  major  portion  of  the  bones  found  together 
at  the  bottom  of  the  pit  belong  to  one  specimen,  but  there  is  also  no  question  that 
some  bones  of  a  second  individual  found  their  way  into  the  hole,  as  there  is  an  excessive 
number  of  dorsal  vertebrae  and  there  is  a  second  axis.  Only  a  very  few  of  the  char- 
acteristic dorsal  plates  of  Desmatosuchus  were  found  among  the  abundant  remains  of 
Phytosaurs  in  the  adjacent  regions  of  the  county,  suggesting  the  comparative  rarity  of 
the  form  and  perhaps  its  restriction  to  a  certain  habitat.  The  peculiar  condition  under 
which  the  specimen  was  found  and  the  fact  that  no  other  bones  were  found  nearer  to 
it  than  a  half  mile  must  again  be  emphasized  by  the  author  as  justification  for  associating 
the  bones  in  a  mount. 

A  preliminary  description  of  this  form  has  been  published  in  the  Journal  of 
Geology1. 

The  material  collected  consists  of  the  skull  lacking  the  lower  jaw  and  the  anterior 
end  of  the  nose,  the  vertebral  column,  which  is  apparently  complete  to  the  sacrum  and 
a  few  caudal  vertebras,  the  dorsal  armor  of  the  body  and  a  portion  of  the  tail,  an  im- 
perfect right  scapula,  and  a  portion  of  the  right  side  of  the  pelvis.  A  fragment  of  one 
of  the  long  bones  is  the  single  bit  of  evidence  of  the  skeleton  of  the  limbs.  One  small, 
irregular  plate  was  found  with  the  mass  of  vertebras  and  may  be  taken  as  evidence  of 
the  presence  of  isolated  plates  upon  the  sides  or  abdomen. 

The  greater  part  of  the  material  was  found  in  an  irregular  heap,  with  no  continuity 
except  in  the  cervical  region  and  a  few  of  the  dorsals.  A  few  of  the  plates  seem  to 

1  Case,  E.  C.,  Preliminary  Description  of  a  New  Suborder  of  Phytosaurian  Reptiles,  with  a  Description  of  a 
New  Species  of  Phytosaurus,  Journal  of  Geology,  vol.  XXVIH,  No.  6,  p.  524,  1920. 


THE   UPPER   TRIASSIC    OF   WESTERN   TEXAS. 


27 


have  retained  their  normal  position.  The  restoration  of  the  skeleton  has  been  accom- 
plished by  placing  the  bones  in  their  most  evident  position,  with  such  checks  as  their 
original  position  afforded. 

The  skull. — In  many  of  its  characters  the  skull  resembles  that  of  the  Phytosauria, 
but  differs  so  radically  in  others  that  it  must  be  placed  at  least  in  a  separate  suborder. 
The  close  occlusion  of  the  sutures  and  the  condition  of  preservation  has  made  the 
determination  of  the  most  of  the  sutures  impossible.  The  surface  of  the  skull  has  been 
most  carefully  cleaned  with  a  needle  and  has  been  treated  with  acid  to  remove  the 
pyrite  and  the  other  matrix.  It  has  been  repeatedly  examined  under  a  binocular 
microscope,  so  that  the  author  feels  certain  that  all  possible  traces  of  the  sutures  have 
been  made  out. 


bo  bs 


FIG.  7. — Skull  of  Desmalosuchus  spurensis, 

A.  I'pper  surface.  X  0.3.  B.  Lateral  surface.  X  0.3.  C.  Posterior  surface.  X  0.3.  D.  Lower  surface  of  pos- 
terior portion.  X  0.6.  E.  Lateral  surface  of  wall  of  brain-case.  X  0.6. 

bs.,  basisphenoid;  ps.,  parasphenoid  rostrum;  ot.,  otic  channel;  als.,  alisphenoid;  pro.,  prootic;  ot.,  otic  opening; 
op.,  opisthotic;  II-XII,  outlets  of  cranial  nerves. 


28  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

The  general  shape,  with  the  exception  of  the  anterior  end  of  the  nose,  is  shown  in 
figure  7  and  plate  5.  The  small  size  relative  to  the  body  is  a  striking  difference  from 
the  condition  found  in  the  Phytosauria.  It  is,  of  course,  uncertain  just  what  length 
was  attained  by  the  nose,  but  from  the  position  of  the  nares,  the  shape  oi  the  nose, 
and  the  approximation  of  the  maxillaries,  it  is  apparent  that  not  a  great  deal  is  missing. 
The  lack  of  a  second  temporal  fenestra  is  the  most  striking  character  of  the  skull.  This 
might  be  considered  as  a  primitive  character  were  it  not  for  the  associated  characters 
of  the  lack  of  a  pineal  foramen  and  the  small  size  of  the  post-temporal  openings,  which 
amount  to  no  more  than  foramina.  The  nearly  complete  closure  of  the  posterior 
surface  of  the  skull,  with  the  single  temporal  opening  and  the  prolongation  of  the  jugal 
forward  and  downward,  led  the  author  to  repeated  attempts  to  trace  some  resemblance 
between  this  form  and  those  from  South  Africa,  especially  the  Deinocephalia — attempts 
that  were  just  as  repeatedly  demonstrated  to  be  useless;  but  superficial  suggestions 
recalled  the  South  African  forms  many  times.  The  presence  of  the  deep  notch  below 
the  orbit,  with  the  projecting  edges  of  the  jugal  and  the  maxillary,  led  to  the  suggestion 
that  the  temporal  opening  was  the  upper  one  and  that  the  lower  part  of  the  temporal 
region  was  broken  away  and  lost.  This  suggestion  was  also  made  to  the  author 
independently,  by  both  Doctor  von  Huene  and  Doctor  Watson,  after  their  consideration 
of  the  figures  published  in  the  preliminary  description  of  Desmatosuchus.  The  ideas 
of  these  friends  are  indicated  in  figure  8.  This  is,  however,  impossible,  as  the  lower 
edges  of  the  bones  in  this  region  are  paper-thin  and  complete;  moreover,  the  position, 
character,  and  form  of  the  bones  on  the  two  sides  are  practically  identical,  a  condition 
that  is  almost  inconceivable  if  part  had  been  accidentally  lost. 

The  lateral  aspect  of  the  skull  (fig.  7  A  and  plate  5s). — As  mentioned  above,  the 
anterior  end  is  missing,  from  about  the  anterior  third  of  the  narial  opening  forward. 
The  maxillaries  are  elongate,  with  only  a  limited  exposure  on  the  sides  of  the  skull; 
the  alveolar  edge  is  slightly  convex  antero-posteriorly.  At  the  anterior  end,  below  the 
anterior  half  of  the  nares,  there  is  the  appearance,  on  both  sides,  of  a  wedge-like  insertion 
of  a  posterior  prong  of  some  bone  in  front.  If  this  is  a  distinct  element  it  can  only  be 
a  part  of  the  premaxillary.  Between  the  narial  and  the  antorbital  openings  the  upper 
edge  of  the  maxillary  rises  in  a  process  which  is  reflected  at  its  upper  end  and  joins  the 
lachrymals  and  the  nasals;  the  suture  is  here  clear  and  distinct.  The  line  of  juncture 
between  the  maxillary  and  the  lachrymal  can  not  be  made  out  on  either  side,  but  a 
break  on  the  left  side  of  the  skull,  which  possibly  may  be  along  the  line  of  the  suture, 
indicates  that  the  suture  was  perhaps  convex  downward,  permitting  the  maxillary  to 
form  the  posterio-inferior  border  of  the  antorbital  opening.  The  upper  edge  of  the 
maxillary  forms  the  anterior  half  of  the  lower  border  of  the  orbit;  the  suture  between 
it  and  the  jugal  is  inclined  backward  and  downward.  From  a  point  at  the  posterior 
edge  of  the  dental  series  the  lower  edge  of  the  maxillary  is  inclined  somewhat  abruptly 
backward  and  downward,  terminating  in  a  blunt  point  of  thin  bone.  The  posterior 
edge  of  this  process  is  nearly  straight  and  forms  the  anterior  edge  of  a  nearly  rectangular 
notch  which  lies  below  the  orbit  and  between  the  maxillary  and  the  jugal.  A  posterior 
narrow  prong  of  the  maxillary  which  articulates  with  the  jugal  above  forms  the  upper 
border  of  the  notch.  The  complete  edges  of  the  bones  outlining  this  notch  and  the 
almost  exact  similarity  of  the  two  sides  show  that  this  is  a  notch  and  not  the  upper  part 
of  a  second  temporal  opening.  It  is  a  structure  which  has  not  previously  been  noted, 
so  far  as  the  author  knows,  in  any  fossil  skull.  There  are  12  clearly  defined  sockets 
on  the  alveolar  edge  of  the  maxillary  of  the  left  side  and  13  on  the  right;  these  indicate 
teeth  of  moderate  size  with  nearly  cylindrical  roots.  There  is  no  indication  of  enlarged 
teeth  at  the  anterior  end  and  there  is  no  suggestion  of  antero-posteriorly  elongate  teeth 


CASE 


PLATE  5 


B 


Desmatosuchus  spurensis,  skull,  No.  7476,  U.  of  Mich.     All  figures  X0.36. 
A.  Upper  surface.     B.  Lateral  surface.     C.  Lower  surface.     D.  Posterior  surface. 


T1IK    ri'l'KK    TKIASSir    OF    WESTERN    TEXAS.  29 

such  as  occur  in  the  posterior  part  of  the  jaws  in  the  Phytosauria.  The  sockets  of  the 
median  part  of  the  series  sorm  a  little  larger  than  those  of  the  anterior  or  posterior  ends; 
this  may  be  due  to  the  condition  of  the  specimen.  Only  a  single,  badly  rotted  tooth 
was  found  associated  with  the  specimen  and  from  this  nothing  can  be  made  out. 

The  nasals  are  elongate  bones  lying  in  the  normal  position,  forming  the  upper 
edge  of  the  narial  openings  and  separated  from  the  maxillaries  and  the  lachrymals  by 
distinct  sutures.  The  posterior  edge  can  not  be  made  out  exactly,  but  a  suture  is 
traceable  for  a  short  distance  from  a  point  a  little  in  front  of  the  posterior  edge  of  the 
antorbital  opening  toward  the  median  line. 

No  trace  of  a  septo-maxillary  can  be  made  out. 

The  lachrymal  forms  the  upper  border  of  the  antorbital  opening  and  is  separated 
from  the  nasal  and  the  prefrontal  by  a  distinct  suture.  It  forms  the  broad  bar  between 
the  orbit  and  the  antorbital  opening  and  joins  the  maxillary  below,  but  the  suture,  as 
stated  above,  can  not  be  made  out  definitely.  The  portions  of  the  lachrymal  and  the 
maxillary  adjacent  to  the  upper  part  of  the  antorbital  opening  are  smooth  and  evidently 
afforded  attachment  to  a  strong  muscle  which  helped  to  close  the  jaws.  The  upper 
portion  is  marked  by  a  deep  but  relatively  small  sculpture.  A  foramen  enters  the 
bone  on  the  inner  rim  of  the  orbit. 

The  jugal  occupies  the  normal  position,  forming  the  posterior  half  of  the  lower 
rim  and  the  lower  half  of  the  posterior  rim  of  the  orbit.  The  union  with  the  maxillary 
is  sharply  defined.  The  posterior  border  of  the  notch  beneath  the  orbit  is  formed  by 
the  jugal.  The  lower  border  rises  sharply  from  the  posterior  lower  corner  of  the  notch 
to  the  articular  region  of  the  skull.  The  suture  between  the  jugal  and  the  postorbital 
is  very  distinct ;  the  two  bones  meet  at  about  the  middle  of  the  slender  postorbital  bar. 
The  jugal  narrows  towards  the  rear  and  forms  the  major  part  of  the  bar  closing  the 
temporal  opening  below.  Neither  the  position  nor  the  outline  of  the  jugal-quadrato- 
jugal  suture  can  be  made  out. 

The  limits  of  the  quadratojugal  can  not  be  made  out,  but  it  is  evident  that  it  is 
a  small  element.  The  posterior  lower  angle  of  the  skull  is  narrow  and  the  bar  behind 
the  temporal  opening  is  even  narrower.  The  whole  region  is  more  slender  than  appears 
at  first  sight,  for  the  distal  end  of  the  opisthotic  appears  on  the  lateral  surface  and 
increases  the  apparent  size  of  the  angle  when  seen  in  profile. 

The  sutures  outlining  the  prefrontal,  postfrontal,  and  frontal  can  not  be  followed ; 
the  whole  region  is  very  rugose  and  the  most  careful  inspection  has  failed  to  reveal  more 
than  short  traces  of  the  lines  of  separation. 

The  postorbital. — -Just  posterior  to  the  heavy  rugose  knob  which  marks  the  upper 
posterior  angle  of  the  orbit,  a  suture  can  be  traced  for  a  short  distance  upon  the  smooth 
surface  of  the  skull  on  both  sides;  this  evidently  marks  the  posterior  edge  of  the  post- 
orbital. 

The  squamosal  begins  at  the  suture  just  mentioned;  the  anterior  part  lies  in  the 
smooth  area  above  the  temporal  foramen;  the  posterior  portion  is  slightly  but  abruptly 
elevated  and  forms  a  protecting  point  on  the  back  of  the  skull.  The  edge  of  the  abruptly 
elevated  portion  is  continued  downward  and  backward  and  forms  the  posterior  edge  of 
the  lateral  temporal  opening  until  it  meets  the  quadratojugal  at  some  undetermined 
point. 

The  upper  surface  of  the  skull  (fig.  7  A  and  plate  5  A). — The  skull  is  narrow  in  front 
and  gradually  widens  to  the  posterior  edge.  The  nasals  form  a  little  more  than  the 
anterior  half;  their  surface  is  sculptured  a  little  more  deeply  on  the  median  than  on  the 
outer  parts.  The  median  suture  is  traceable  to  the  posterior  edge  of  the  nasals,  but 
from  there  back  is  indistinguishable;  it  is  entirely  obliterated  in  the  parietal  region, 


30  JtEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

where  the  smooth  area  permits  the  most  careful  examination.  This  smooth  area  is 
the  surface  of  a  shallow  depression  which  runs  directly  across  the  top  of  the  skull,  from 
a  point  opposite  the  anterior  half  of  the  upper  edge  of  the  temporal  opening  to  the  same 
point  on  the  other  side;  its  posterior  border  is  somewhat  sharply  elevated  by  the 
rugosity  of  the  surface  of  the  squamosal  and  parietal  bones,  and  it  is  divided  by  a  low 
ridge  on  the  median  line  of  the  skull.  The  most  of  the  upper  surface  is  so  deeply 
sculptured  that  the  sutures  are  not  visible,  but  it  appears  from  the  arrangement  of  the 
sculpture  that  the  frontals,  paired  or  unpaired,  occupy  a  heart-shaped  area  from  about 
the  posterior  line  of  the  orbits  as  far  forward  as  the  nasals.  There  is,  on  each  side,  a 
deep  groove  or  elongate  pit  just  within  the  very  rugose  upper  border  of  the  orbit.  At 
the  posterior  inner  edge  of  this  groove  there  is  the  center  of  rugosity  which  may  mark 
the  anterior  inner  corner  of  the  postorbital. 

The  posterior  face  of  the  skull  (fig.  7  c  and  plate  5  D).— This  face  of  the  skull  was 
readily  freed  from  the  matrix  and  presents  a  smooth  surface  of  uninjured  bones,  upon 
which  no  marks  or  sutures  could  be  missed.  The  whole  face  is  semicircular,  with  the 
prominent  occipital  condyle  in  the  center  of  the  horizontal  lower  edge.  The  surface 
is  completely  closed,  with  the  exception  of  the  post-temporal  openings  (which  are  so 
small  as  to  be  reckoned  as  little  more  than  foramina)  and  the  large  foramen  magnum. 
In  the  median  line  above  there  is  a  thin  but  prominent  ridge  flanked  by  vertically 
elongate  pits.  The  whole  surface  slants  backward  at  a  slight  angle  and  is  concave 
from  side  to  side  above  the  line  of  the  opisthotics;  below  this  line  the  distal  ends  of  the 
opisthotics  slant  more  acutely  backward,  increasing  the  concavity.  The  line  of  division 
between  the  opisthotics  and  the  plate  above  is  traceable  inward  for  a  short  distance 
beyond  the  post-temporal  openings;  the  sutures  between  the  exoccipitals  and  the  ad- 
jacent elements  are  completely  obliterated.  Just  above  the  foramen  magnum  there  are 
small  prominences  which  suggest  the  presence,  in  the  complete  skeleton,  of  a  proatlas. 
The  opisthotics  turn  sharply  outward  from  their  junction  with  the  exoccipital  portion; 
their  posterior  faces  are  smooth,  with  a  low  ridge  which  runs  outward  and  slightly 
downward  on  the  inner  half.  The  distal  portion  is  slightly  expanded  and  the  fairly 
broad,  somewhat  triangular  distal  ends  are  visible  from  the  rear. 

Between  the  distal  end  of  the  triangular  terminal  face  of  the  opisthotic,  which 
points  forward,  and  the  quadratojugal  there  is  visible  a  wedge-like  surface  of  bone 
which  must  be  a  portion  of  the  nearly  concealed  quadrate.  There  is  no  trace  of  a  quad- 
ratojugal foramen.  The  occipital  condyle  is  nearly  spherical  and  is  supported  upon 
a  well-defined  neck;  there  is  no  trace  of  a  pit  marking  the  forward  extension  of  the 
notochord.  A  distinct  line  marks  the  contact  of  the  posterior  plate  of  the  skull  with 
the  squamosal-quadratojugal;  the  plate  sends  a  long  process  to  fill  the  space  between 
the  distal  end  of  the  opisthotic  and  squamosal-quadratojugal. 

The  lower  surface  of  the  skull  (fig.  7  D  and  plate  5  c)  .• — The  pterygoids  and  the  bones 
of  the  palatal  region  are,  most  unfortunately,  absent,  but  the  bones  of  the  brain-case 
are  so  perfectly  preserved  that  all  the  foramina  can  be  made  out;  the  sutures  are  all" 
closed  and  can  not  be  traced.  The  phytosauroid  characters  are  seen  in  the  prominent 
basioccipital-basisphenoid  mass  lying  well  below  the  level  of  the  occipital  condyle,  in 
the  deep  pit  which  lies  in  the  usual  position  of  the  openings  of  the  Eustachian  canals, 
in  the  strong  basipterygoid  processes  of  the  basisphenoid,  and  in  the  strong  alisphenoids 
rising  to  the  roof  of  the  skull  and  firmly  attached  to  it.  The  primitive  character  is 
shown  in  the  evident  loose  attachment  of  the  pterygoids  and  the  prominent,  free, 
parasphenoid  rostrum. 

The  basioccipital. — Anterior  to  the  condyle  the  lower  surface  of  the  bone  bends 
sharply  downward  and  forms,  or  approaches  close  to,  the  posterior  edge  of  the  deep 


THE    UPPER   TRIASSIC   OF   WESTERN   TEXAS.  31 

pit  in  the  basisphenoid.  The  suture  between  it  and  the  basisphenoid  is  not  distinct, 
but  on  either  side  of  the  pit  there  is  a  deep  groove  which  marks  the  position  of  the- 
suture;  it  is  possible  that  the  sutural  region  was  occupied  in  life  by  a  considerable  mass 
of  cartilage,  which  in  its  decay  has  left  the  groove.  The  upper  part  of  the  anterior 
edge  is  marked  by  a  sharp,  thin  ridge;  just  anterior  to  this  is  a  large  foramen  through 
which  passed  the  jugular  vein  and  the  IX,  X,  and  XI  nerves.  Near  the  posterior  edge 
there  are  small  foramina  in  the  exoccipital  portion  of  the  complex,  which  permitted 
the  escape  of  the  XII  nerves. 

The  basisphenoid.- — The  lower  surface  is  marked  by  the  presence  of  a  remarkably 
large  and  deep  conical  pit.  This  is  in  the  position  of  the  openings  of  the  Eustachian 
canals  in  the  Crocodilia,  but  the  pit  was  thoroughly  cleaned  out  and  no  traces  of  such 
openings  could  be  detected.  On  either  side  of  the  pit  the  bone  is  thickened  and  passes 
forward  to  form  the  prominent  basipterygoid  processes.  Posterior  to  the  processes 
the  sides  of  the  bone  are  marked  by  a  groove  and  then  swell  backward  and  outward 
to  the  edge  of  the  groove  which  marks  the  line  between  the  basisphenoid  and  the 
basioccipital.  Between  the  basipterygoid  processes  there  is  a  thin  parasphenoid  rostrum 
of  considerable  vertical  extent.  The  anterior  portion  has  been  injured  by  decay,  but 
it  is  apparent  that  not  a  great  deal  has  been  lost.  The  upper  part  of  the  posterior  end 
of  this  process  is  excavated  to  receive  the  lower  end  of  the  infundibulum  and  the  edges 
of  this  excavation  are  continuous  with  the  alisphenoids  above.  The  anterior  face  of 
the  basisphenoid  is  rather  broad  and  slightly  inclined  backward  to  the  posterior  face 
of  the  cavity  for  the  infundibulum.  Near  the  middle  of  this  face  there  is  a  pair  of 
foramina  for  the  entrance  of  the  internal  carotid  arteries.  The  point  of  juncture  of 
the  basisphenoid  and  the  bones  above  is  not  determinable.  From  the  bottom  of  the 
pit  on  the  upper  surface  of  the  posterior  portion  of  the  parasphenoid  rostrum  foramina 
run  through  the  sides  of  the  basisphenoid  to  open  into  the  lower  part  of  the  groove 
described  as  lying  posterior  to  the  basipterygoid  processes;  the  function  of  these  foramina 
is  not  known. 

The  walls  of  the  brain-case  (fig.  7  E)  are  formed  by  the  alisphenoids,  the  prootics, 
the  epiotics  (?),  and  the  opisthotics,  which  form  a  solid  lateral  mass  without  distinguish- 
ing sutures.  The  outer  surface  of  the  brain-case  is  marked  by  two  distinct  ridges. 
The  first  starts  below  the  origin  of  the  bar  between  the  orbit  and  the  temporal  opening 
and  descends  almost  vertically,  becoming  continuous  with  the  anterior  edge  of  the 
alisphenoid  at  a  point  about  one-third  of  its  height  above  its  origin  from  the  parasphenoid 
rostrum.  This  ridge  probably  marks  the  line  of  contact  between  the  prootic  and  the 
alisphenoid. 

The  lower  ends  of  the  alisphenoids  are  closely  approximated,  forming  a  narrow 
opening  through  which  the  hypophysis  extends  into  the  infundibular  cavity  below; 
above  this  the  anterior  edges  of  the  bones  rise  nearly  vertically,  with  a  slight  notch 
which  permitted  the  escape  of  the  III  and  IV  nerves;  at  about  one-half  of  their  height 
the  edges  incline  gently  forward  and  contract  into  a  second  notch  which  marks  the 
escape  of  the  II  pair  of  nerves;  beyond  this  they  incline  more  sharply  forward  and 
diverge  to  their  contact  with  the  upper  wall  of  the  skull. 

Posterior  to  the  first  ridge,  the  walls  of  the  brain-case  are  concave  and  perforated 
by  the  large  foramina  for  the  V  nerves;  the  bulk  of  this  portion  of  the  wall  is  formed  by 
the  prootic.  The  second,  or  posterior,  ridge  on  the  wall  of  the  brain-case  comes  sharply 
forward  from  the  rear.  Its  posterior  portion  is  formed  by  the  lower  edge  of  the  opisthotic; 
just  above  the  otic  opening  it  bends  sharply  downward  and  forward  and  very  nearly 
reaches  the  lower  end  of  the  first  ridge.  There  are  no  sutures  visible  in  the  space  between 
these  ridges,  but  there  is  a  short,  low  elevation  extending  forward  from  just  below  the 


32 


NEW    REPTILES   AND    STEGOCEPHALIANS   FROM 


upper  posterior  portion  of  the  temporal  opening,  which  carries  slight  rugosities  and 
may  indicate  the  location  of  the  suture  between  the  epiotic  and  prootic.  The  epiotic, 
if  ever  a  distinct  element,  is  fused  with  the  opisthotic  in  the  specimen.  The  edge  of 
the  anterior  half  of  the  posterior  ridge  is  elevated  and  behind  it  is  a  groove  which  is 
continuous  with  the  groove  on  the  side  of  the  basisphenoid.  On  the  inner  end  of  the 
opisthotic  there  are  two  openings — an  upper,  the  otic  opening,  and  a  lower,  the  jugular 
foramen. 

The  position  and  form  of  the  quadrate  is  one  of  the  puzzling  features  of  the  skull. 
Between  the  distal  end  of  the  opisthotic  and  the  quadratojugal  is  a  deep  pit,  partly 
cut  off  in  front  by  a  ridge  which  runs  from  the  inner  side  of  the  posterior  end  of  the 
jugal-quadratojugalbar  to  the  opisthotic.  The  quadrate  apparently  occupies  the  bottom 
of  this  pit,  and  the  articulation  with  the  lower  jaw  must  have  been  formed  by  the  con- 
cave surface,  but  no  distinct  articular  surface  is  visible.  If  this  interpretation  is  correct, 
the  quadrate  fills  a  small  triangular  area  between  the  distal  end  of  the  opisthotic  and 
quadratojugal,  forms  the  bottom  of  the  pit  described,  and  runs  forward  for  a  short 
distance  on  the  inner  side  of  the  opisthotic  and  for  an  uncertain,  but  not  great,  distance 
on  the  cranial  wall.  At  best  it  must  have  been  a  relatively  small  and  inconspicuous 
bone. 


pt.f? 


?  "3 


FIG.  8. — Restoration  of  skull  of  Desmatosuchus. 

After  ideas  suggested  by  Watson  and  von 
Huene.  Dotted  portions  are  supposed 
to  have  been  lost. 

opo.,  distal  end  of  the  opisthotic.  Other  lettering 
as  usual. 


In  comparing  the  skull  with  that  of  other  forms,  it  is  at  once  apparent  that  its 
closest  relations  lie  with  the  Parasuchia,  but  the  differences  are  so  fundamental  that 
it  can  not  be  placed  in  that  order.  The  most  notable  differences  are  the  single  temporal 
foramen,  the  lateral  and  anterior  position  of  the  nares,  and  the  extremely  reduced 
condition  of  the  quadrate  bone.  The  last  is  the  most  fundamental.  The  lateral 
position  of  the  nares  is  found  in  the  Pseudosuchians  and  in  some  primitive  Parasuchians. 
The  development  of  the  upper  temporal  opening  is  so  irregular,  though  constantly 
present,  in  the  two  groups  that  its  complete  disappearance  would  be  no  great  step  in 
specialization;  or  its  absence  might  be  regarded  as  of  primitive  character,  since  it  has 
become  apparent  that  the  presence  of  two  temporal  openings  and  arches  is  not  the 
primitive  condition  of  the  Reptilia.  The  great  reduction  of  the  quadrate  is  a  character 
which  does  not  appear  outside  of  the  South  African  phyla,  which  can  hardly  be  com- 
pared with  this  form,  for  in  those  phyla  the  reduction  of  the  quadrate  is  accomplished 
in  an  entirely  different  manner.  In  most  of  the  Reptilia  the  quadrate  has  a  greater  or 
less  vertical  extent  upon  the  side  of  the  skull  and  is  not  always  closely  associated  with 
the  bones  of  the  brain-case,  its  main  associations  being  with  the  bones  of  the  suspensorial 
region.  Only  in  the  Crocodilia  (sens,  lat.)  does  the  quadrate  extend  far  inward,  having 
relations  with  the  wall  of  the  brain-case  and  the  bones  of  the  otic  region.  It  is  not 
possible  in  the  specimen  to  determine  whether  the  quadrate  has  the  relations  figured 
by  Huene  for  the  Parasuchia  (Geolog.  u.  Paleont.  Abhdlg.,  vol.  x,  N.  F.,  Hft.  1,  p.  31, 
fig.  20),  permitting  the  squamosal,  epiotic,  and  prootic  to  appear  in  the  posterior  lateral 


THE   UPPER   TRIASSIC    OF   WESTERN   TEXAS.  33 

wall  of  the  brain-case,  but  it  seems  probable  that  all  of  these,  except  possibly  a  distinct 
epiotic,  had  such  an  arrangement  and  that  the  quadrate  runs  forward  on  the  brain-case 
nearly  the  full  length  of  the  opisthotic  and  joined  the  prootic  in  front  and  perhaps  the 
squamosal  above.  The  quadratojugal  did  not  send  any  process  forward  on  the  anterior 
or  lower  edge  of  the  quadrate,  as  in  the  Crocodilia. 

In  figure  8  is  given  a  sketch  of  the  condition  of  the  skull  as  originally  imagined  by 
the  author  and  as  suggested  to  him  by  both  Doctor  F.  v.  Huene  and  Doctor  D.  M.  S. 
Watson.  Reasons  have  been  given  above  why  this  suggestion  must  be  rejected,  but 
there  is  much  weight  in  the  objection  offered  by  Doctor  Watson  that  in  the  phytosauroid 
reptiles  the  basicranial  region  is  never  so  far  below  the  quadrate.  Future  discoveries 
may  show  that  the  alternative  restoration  is  correct  and  that  Desmatosuchus  must  be 
placed  among  the  Parasuchia.  At  present  the  restoration  and  explanation  here  given 
seem  to  the  author  the  only  ones  possible. 

Description  of  the  endocranial  cast  (plate  6,  figs.  A,  B,  c). — A  description  and 
discussion  of  the  endocranial  cast  of  Desmatosuchus  has  already  been  published1  and 
only  a  portion  of  it  is  repeated  here. 

"The  cranial  cavity  of  Desmatosuchus  was  completely  cleared  out,  leaving  the  surface  of  the 
bone  in  good  condition  with  all  the  pits  and  foramina  clearly  marked.  As  may  be  seen  in  the  fig- 
ures, the  cast  as  finally  secured  shows  the  general  form  and  proportions  of  the  brain  cavity  and  the 
positions  of  the  main  outlets.  The  anterior  wall  of  the  cavity  was  entirely  cartilaginous  or  mem- 
branous, and  as  this  portion  was  not  preserved  in  the  fossil  the  opening  was  stopped  with  plastic 
clay  which  is  easily  detected  in  the  figures.  For  this  reason,  the  form  of  the  olfactory  tract  and  of 
the  pituitary  body  is  not  completely  shown. 

"The  olfactory  tract  was  evidently  large,  as  in  most  of  the  primitive  forms,  and  extended  well 
forward  directly  beneath  the  upper  wall  of  the  skull.  The  cerebral  portion  was  relatively  small, 
scarcely  any  swelling  being  revealed  in  this  part  of  the  cast  except  at  the  posterior  end  of  the 
prosencephalic  region.  The  anterior-lower  part  of  this  region  was  enclosed  by  the  ali-,  orbitosphenoid 
bones,  and  the  approximation  of  the  bones  of  the  two  sides  forms  notches  in  two  places  which  indi- 
cate the  points  of  escape  of  the  nerves  which  supplied  the  eye.  No  indication  of  the  origin  of  the 
II,  III,  or  IV  pair  of  nerves  is  shown  on  the  cast,  and  no  outlets  except  the  notches  mentioned. 

"It  is  impossible  in  the  cast  to  distinguish  between  the  diencephalic  and  the  mesenccphalic 
regions  of  the  brain,  but  the  area  occupied  by  these  two  is  marked  by  a  slight  but  distinct  depres- 
sion, which  is  outlined  by  definite  elevations,  the  posterior  one  amounting  to  a  low,  sharp  ridge. 
From  this  depression  rise  the  processes,  above  and  below,  which  may  be  referred  to  in  general 
terms  as  the  epiphysis  and  the  pituitary  body. 

' '  The  upper  process  is  complex  and  is,  perhaps,  composed  of  two  parts.  Just  posterior  to  the 
edge  of  the  prosencephalic  portion  there  are  two  protuberances  which  mark  the  position  of  a  pair 
of  deep  pits  in  the  upper  wall  of  the  brain-case.  In  cleaning  the  skull  it  was  impossible  to  be  cer- 
tain that  the  bottom  of  these  cavities  had  been  reached,  but  it  seemed  probable  that  it  had.  With 
the  aid  of  a  dentist's  mouth-mirror  and  fine  curved  awls  the  pyrite  filling  was  picked  out  until  it 
seemed  that  the  bottom  had  been  reached,  but  because  of  the  inaccessibility  of  the  cavities  and  their 
small  diameter  it  is  possible  that  the  cavities  may  have  been  deeper  and  even  that  they  may  be 
the  entrances  to  foramina.  Cope,  in  describing  the  endocranial  casts  of  a  Phytosaur,  Belodon, 
and  of  a  cotylosaurian  reptile,  Diadectes,  sfx'aks  of  the  'lateral  processes  of  the  epiphysis'  and  in 
describing  the  skull  of  Belodon  speaks  of  the  process  as  lying  in  a  'large  canal  which  enters  the 
posterior  part  of  the  orbit.'  To  this  canal  he  gave  the  name  of  the  orbitopineal  process  on  the 
casts.  The  function  of  this  canal  he  was  unable  to  determine,  but  suggests  that  it  carried  a  nerve 
or  blood-vessel.2  In  his  earlier  papers  he  was  inclined  to  the  belief  that  Diadectes  was  blind  because 
he  could  find  no  outlet  for  the  optic  nerve  and  because  the  structure  of  the  animal  suggested  that 

'Case,  E.  ('..  On  an  Kmloeranial  C'a-st  from  a  Reptile,  Desmatosuchwi  spurensis,  from  the  Upper  Tria.-wic  of 
western  Texas,  Journal  of  Comparative  Neurology,  vol.  33,  No.  2,  p.  133,  1921. 

8  Dr.  R.  L.  Moodie,  in  conversation  with  the  author,  has  suggested  that  these  processes  may  indicate  a  portion 
of  the  course  of  the  ductus  endolymphaticus. 


34  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

it  was  burrowing  in  habit;  as  the  parietal  foramen  is  exceptionally  large  in  this  form,  he  was  in- 
clined to  believe  that  the  orbitopineal  canal  might  have  carried  a  nerve  from  the  large,  probably 
functional  eye  which  occupied  the  parietal  foramen,  which  in  part  supplied  the  necessary  vision. 
It  is  impossible  to  tell  whether  such  a  canal  existed  in  Desmatosuchus,  but  if  it  was  present  it  was 
very  small,  and  the  author  of  this  paper  is  inclined  to  believe  that  it  did  not  exist.  Moreover, 
there  is  a  decided  difference  in  the  endocranial  casts  in  this  region.  In  Belodon  and  Diadectes  the 
processes  are  large  and  rise  from  the  sides  of  the  epiphysis,  in  Desmalosuchus  they  are  small  and  are 
entirely  anterior  to  the  epiphysis.  It  is  possible  that  if  a  true  cast  of  the  brain  could  be  obtained 
the  origin  of  the  processes  might  be  found  to  be  the  same  in  all,  but  as  the  casts  were  all  made  from 
empty  cavities  a  similar  origin  should  be  apparent. 

"The  epiphysis  is  very  different  in  form.  In  Belodon  and  Diadectes  theie  is  a  strong  posterior 
process,  and  Cope  describes  the  epiphysis  of  the  former  as  'subquadrate.'  The  orbitopineal  pioccss 
extends  either  directly  outward  from  the  side,  Diadectes,  or  outward  and  forward,  Belodon.  In 
Desmatosuchus  the  epiphysis  is  erect  and  narrow  antero-posteriorly  with  no  posterior  process.  In 
both  Belodon  and  Desmatosuchus  the  processes  referred  to  as  the  epiphysis  are  casts  of  a  deep  pit 
on  the  under  side  of  the  skull  in  the  exact  position  of  the  pineal  foramen  in  other  reptiles,  but  in 
neither  of  these  is  the  roof  perforated.  In  looking  up  this  matter  the  author  has  found  that  much 
uncertainty  exists  as  to  the  exact  character  of  this  process  in  the  brain;  it  is  known  that  both  the 
epiphysis  and  the  paraphysis  may  reach  large  size  and  that  either  one  may  terminate  in  a  func- 
tional eye;  at  least,  either  one  may  carry  organs  which  possess  the  histological  structures  of  the 
retina  and  the  crystalline  lens.  In  some  forms  there  has  also  been  found  a  third  evagination  of  the 
brain,  posterior  to  the  epiphysis,  called  the  pineal  organ,  which  has  a  similar  histological  structure. 
Wilder,  in  his  History  of  the  Human  Body,  states  that  it  is  the  paraphysis  which  was  developed  in  the 
extinct  Stegocephalia  and  filled  the  parietal  foramen,  and  the  epiphysis  which  was  developed  in 
the  reptiles,  birds,  and  mammals.  On  the  other  hand,  it  is  known  that  the  epiphysis  is  not  devel- 
oped in  the  modern  alligator.  The  term  epiphysis  is  used  in  this  paper  only  in  a  general  sense  and 
without  knowledge  of  its  true  nature. 

' '  On  the  lower  side  of  the  diencephalic  region  of  the  cast  is  the  second  process ;  this  represents 
the  combined  infundibulum  and  the  saccus  vasculosus,  or  the  pituitary  body.  Only  the  posterior 
and  lower  borders  are  shown,  for  the  anterior  part  was  enclosed  by  the  cartilaginous  anterior  wall 
of  the  skull  which  was  lost  in  fossilization.  The  process  extended  directly  downward  by  a  narrow 
neck  which  passed  through  a  narrow  notch  formed  by  the  approximation  of  the  alisphenoid  bones 
at  their  lower  borders.  Its  posterior  face  lay  against  the  basisphenoid  bone,  not  penetrating  it, 
and  its  lower  surface  in  an  excavation  on  the  upper  surface  of  the  posterior  part  of  the  parasphenoid. 
The  lower  part  of  the  process  was  enlarged  and  the  posterior  face,  at  least,  extended  backward  at 
a  sharp  angle.  The  lower  end  terminates  in  a  bifurcate  extension  which  is  formed  by  the  casts  of 
the  beginnings  of  two  foramina  which  open  outwardly  and  downward  in  an  excavation  on  the  upper 
surface  of  the  parasphenoid.  These  foramina  continue  and  terminate  in  deep  grooves  on  the  side 
of  the  basisphenoid.  On  the  posterior  face  of  the  process  are  two  small  prominences  which  mark 
the  position  of  two  foramina  on  the  lower  face  of  the  basisphenoid,  evidently  the  openings  for  the 
internal  carotid  arteries. 

"The  posterior  part  of  the  depressed  area  mentioned  above  must  also  include  the  meson- 
cephalic  portion  of  the  brain,  but  there  is  nothing  to  mark  the  presence  of  either  optic  lobes  or  optic 
thalami.  This  does  not,  however,  suggest  either  their  absence  or  relatively  small  size,  for  if  a  cast 
were  made  of  the  cranial  cavity  of  Sphenodon  or  of  an  alligator  no  evidence  of  these  structures 
would  appear,  though  they  are  of  large  size. 

' '  Posterior  to  the  depressed  area  tho  whole  cast  is  curved  sharply  downward  and  then  straight- 
ened out  horizontally  in  the  metencephalic  region.  On  the  lower  edges  of  the  anterior  part  of  this 
region  there  are  large  prominences  which  mark  the  position  of  the  large  foramina  for  the  passage 
of  the  V  pair  of  nerves.  There  is  no  indication  in  the  cast  of  the  division  of  this  nerve  into  its 
parts;  this  must  have  taken  place  external  to  the  cranial  wall.  Within  and  a  little  posterior  to 
these  prominences  is  indicated  the  position  of  a  pair  of  small  foramina  in  the  floor  of  the  skull, 
evidently  the  outlets  for  the  VI  pair  of  nerves.  Posterior  to  the  V  and  at  about  the  middle  of  the 
posterior  part  of  the  cast,  there  are  a  pair  of  processes  on  each  side,  one  almost  directly  above  the 
other.  The  upper  pair  are  the  casts  of  the  otic  cavities  and  mark  approximately  the  position  of 
the  VIII,  and  probably,  also,  the  VII  nerves,  for  these  two  nerves  escape  from  the  skull  of  the  Croco- 


CASE 


PLATE  6 


Desmatosurhii*  x/<i//<  //.s/s,  No.  7476,  U.  of  Mich.     Endocranial  cast.  X  about  0.6. 
A.   Lateral  view.         B.  Upper  view.         C.  Lower  view. 

D.  Dorsal  armor,  side  view  of  lateral  plate  of  dorsal  region.  X  0.23. 

I-',.   Dorsal  armor,. top  view  of  median  plate  of  dorsal  region.  X  0.23. 

F.  Dorsal  armor,  side  view  of  lateral  plate  of  caudal  region.  X  0.23. 

G.  Dorsal  armor,  top  of  fifth  cervical  series.     X  0.32. 

H.  Dorsal  armor,  posterior  view  of  fifth  cervical  series.     X0.32. 


THE   UPPER   TRIASSIC   OF   WESTERN   TEXAS.  35 

dilia  in  almost  the  same  place.  The  otic  cavities  were  injured  in  fossilization  both  by  piessure 
and  by  the  crystallization  of  the  gypsum  and  pyrite  which  filled  the  cavities  of  the  skull.  It  is 
apparent  that  then'  was  a  thin  wall  between  the  otic  cavity  and  the  brain  cavity,  but  this  has 
tx-en  so  injured  that  it  is  impossible  to  determine  the  original  form  of  the  otic  cavity  or  the  form 
and  position  of  the  semicircular  canals. 

"Below  are  the  large  cylindrical  projections  which  filled  large  foramina  carrying  the  IX.  X. 
and  XI  nerves  and  the  jugular  vein.  All  of  these  must  have  escaped  through  a  common  owning, 
as  the  walls  of  the  brain-case  are  very  perfect  in  this  place  and  no  other  openings  are  present. 

"Near  the  posterior  end  of  the  cast  are  slender  processes  which  mark  the  position  of  the  XII 
nerves.  Above  these  processes  there  are  small  prominences  which  filled  pits  in  the  inner  walls  of 
the  exoccipital  bones.  These  pits  were  entirely  cleared,  and  it  is  certain  that  they  were  not  the 
beginnings  of  foramina,  their  meaning  is  unknown. 

"The  whole  metencephalic  portion  of  the  cast  is  rather  high  and  narrow.  It  is  possible  that 
this  is  due  in  some  degree  to  crushing,  but  there  is  no  indication  of  such  crushing  in  the  skull,  and  it 
is  probable  that  it  is  the  true  form.  The  whole  cast  is  very  small  relative  to  the  size  of  the  animal. 
and  even  assuming  that  the  brain  occupied  the  whole  cavity  its  size  would  lie  remarkable,  though 
after  all  it  is  not  much  smaller,  relatively,  than  the  brain  of  Sphenodon  or  of  an  alligator. 

"It  is  difficult  to  make  any  satisfactory  comparison  of  this  endocranial  cast  with  the  one  made 
by  Cope  from  the  specimen  of  Belodon  buceros  because  of  the  unsatisfactory  nature  of  his  figures. 
but  some  points  can  be  made  out.  As  can  be  seen  by  the  figures  in  his  paper,  the  whole  sha]x>  is 
different,  the  cast  from  Belodon  does  not  show  the  sharp  downward  curve  posterior  to  the  middle 
region.  The  cast  of  Desmatosuchus  is  thinner  for  its  height  and  does  not  have  so  long  a  meten- 
cephalic portion. 

"The  epiphysis  lacks  the  posterior  prolongation,  certainly  it  is  not  'subquadrate'  in  form, 
and  the  lateral  processes  rise  in  front  of,  not  at  the  sides  of,  the  epiphysis.  The  olfactory  tracts 
were  much  broader.  The  optic  nerves  did  not  escape  through  distinct  foramina.  Only  the  origin 
of  the  pituitary  body  is  shown  in  Cope's  figures,  but  he  describes  it  as  small  and  occupying  a  fossa 
in  the  base  of  the  cranial  cavity.  These  characters  support  the  evidence  afforded  by  the  bones  of 
the  skull  that  Desmatosuchus  must  be  placed,  at  least,  in  a  distinct  suborder  from  the  Phytosniiriti.'' 

The  vertebral  column  (see  plates  6  to  10). — The  exact  number  of  presacral  vertebrae 
has  never  been  determined  in  the  Phytosauria.  McGregor  says  that  it  is  "practically 
certain  that  there  were  not  less  than  25  or  more  than  27"  in  the  presacral  series.  In 
the  mount  and  restoration  of  Desmatosuchus,  28  vertebras  have  been  included  in  the 
presacral  series;  while  this  number  may  not  be  exactly  correct,  every  consideration 
of  the  condition  of  the  specimen  and  the  character  of  the  vertebrae  indicates  this 
number;  of  all  the  material  found,  three  cervicals,  which  are  obviously  duplicates,  and 
one  dorsal  have  been  excluded  in  making  the  mount.  It  is  possible  that  the  single 
dorsal  should  have  been  included,  but  it  is  apparently  a  duplicate  and  its  inclusion 
would  have  made  the  presacral  series  seem  unduly  long.  This  restoration  is  subject  to 
correction  by  future  discoveries. 

The  atlas  and  axis  (fig.  9  A  to  D). — The  first  two  vertebrae  are  closely  united  but 
not  coossified.  The  shape  of  the  two  is  very  similar  to  that  figured  by  McGregor1 
for  Mystriosuchus.  The  atlantal  ring  is  complete,  with  but  slight  rugosities  indicating 
the  position  of  the  suture  between  the  intercentrum  and  the  neural  arch.  The  arch  is 
completed  above  by  a  thin  plate  which  passes  obliquely  backward  beneath  the  anterior 
end  of  the  neural  spine  of  the  axis.  On  either  side  the  centrum  bears  projections  from 
the  anterior  edge  near  the  lower  level  of  the  neural  canal;  these  are  marked  off  by  a  deep 
notch  below  and  project  sharply  from  the  anterior  edge  of  the  neural  arch  above.  The 
one  on  the  right  side  is  smooth,  as  if  there  were  an  articulation  for  a  proatlas.  This 
may  be  deceptive,  however,  as  the  corresponding  projection  of  the  other  side  does  not 
have  this  appearance.  There  are  strong  projections  from  the  rear  of  the  neural  arch 

'  McGregor,  J.  H.,  American  Museum  Natural  History,  Memoir  ix,  pt.  u.  p.  62. 


36 


NEW   REPTILES   AND    STEGOCEPHALIANS    FROM 


which  extend  back  to  the  middle  of  the  axis  and  carry  distinct  facets  for  articulation 
with  the  anterior  zygapophyses  of  the  axis.  The  lower  face  of  the  centrum  is  broad 
and  flat  or  even  slightly  concave.  On  the  posterior  external  corners  there  are  small 
but  prominent  processes  for  the  capitula  of  the  atlantal  ribs;  smaller  processes,  almost 
destroyed  by  decay,  lie  on  the  sides  of  the  arch  near  the  level  of  the  base  of  the  neural 
canal.  The  anterior  face  is  deeply  concave  below,  forming  a  socket  for  the  nearly 
spherical  occipital  condyle.  The  upper  edges  of  the  face  are  drawn  in  sharply  below 
the  anterior  processes  and  form  the  sides  of  the  deep  notch  which  receives  the  anterior 
end  of  the  odontoid  process.  The  diameter  of  the  neural  canal  is  considerable. 


FIG.  9. — Desmatosuchus  spurensis. 

A.  Upper  surface  of  atlas  and  axis.     B.  Anterior  surface  of  same.     C.  Anterior  surface  of  a 
second  axis,  No.  7504,  U.  of  Mich.     D.  Lateral  surface  of  same.     All  figures  X  0.5. 

The  axis  is  much  larger  than  the  atlas,  and  though  the  sutures  are  closed  it  is 
evident  that  the  vertebra  is  composed  of  the  elements  suggested  by  McGregor,  an 
intercentrum  and  the  axis  proper.  The  neural  spine  is  elongate  and  thin,  except  at 
the  anterior  end,  where  it  is  expanded  and  heavy;  this  portion  lies  upon  the  down- 
wardly and  backwardly  sloping  arches  of  the  atlas.  The  anterior  zygapophyses  are 
covered,  but  are  of  good  size,  with  the  faces  looking  almost  directly  upward.  The 
posterior  zygapophyses  are  nearly  normal  in  form;  they  overhang  the  posterior  edge 
of  the  centrum  for  some  distance.  The  lower  face  of  the  centrum  is  flat  from  side  to 
side  and  concave  antero-posteriorly  on  the  posterior  or  true  axial  portion.  The  process 
for  the  capitulum  is  larger  than  for  the  tuberculum  and  a  little  in  advance  of  it.  The 
neural  canal  is  still  large,  but  smaller  than  in  the  atlas;  the  transverse  diameter  is  the 
larger.  The  posterior  face  of  the  centrum  is  deeply  concave. 

A  second  axis  found  with  the  remains  of  Desmatosuchus,  and  evidently  belonging 
to  an  individual  of  the  same  genus  and  species,  is  even  more  perfect.  In  this  (fig.  9, 
c  and  D)  it  is  seen  that  the  odontoid  process  is  quite  broad;  the  posterior  zygapophyses 
show  a  peculiarity  which  is  continued  backward  for  some  distance  in  the  cervical  series; 
the  posterior  end  of  the  zygapophyses  extends  beyond  the  articular  face  and  on  its 
upper  surface  there  is  a  decided  prominence. 

The  next  two  vertebrae  (fig.  10)  were  found  isolated  in  the  matrix  of  the  specimen 
and  are  regarded  as  the  third  and  fourth  because  of  their  size  and  shape.  They  are  in 
poor  condition,  but  show  the  main  characters.  The  neural  spine  of  the  third  is  partly 
rotted  away,  but  the  base  of  the  spine  indicates  that  it  was  thin  laterally  and  somewhat 
elongate.  It  was  evidently  low.  The  anterior  and  posterior  zygapophyses  are  on 
nearly  the  same  level  and  are  normal  in  form  and  position.  The  transverse  process  is 
elongate  and  extends  nearly  straight  downward,  but  a  little  to  the  rear.  The  sides  of 
the  centrum  are  concave  and  the  lower  end  of  the  transverse  process  is  free  for  some 


CASE 


PLATE  7 


Vertebrae  of  Desmatosuchus  spurensis 
All  figures  X0.45. 

A.  Fifth(?)  cervical. 

B.  Tenth  cervical. 

C.  Twelfth  vertebra. 

D.  Anterior  dorsal. 
E  to  H.  Mid-dorsals. 

I  and  J.  Posterior  dorsals. 
K  and  L.  Anterior  dorsals. 


Till:    I   I'l'KK    THIASSIC    OF   WESTERN   TEXAS. 


37 


distance.  The  capitular  facet  stands  on  a  short  process  (fig.  10)  rising  from  the  anterior 
outer  angle  of  the  lower  face  of  the  centrum;  this  process  is  inclined  slightly  backward. 
The  anterior  face  of  the  centrum  is  nearly  circular;  the  posterior  face  is  oval,  with  the 
long  axis  horizontal.  The  neural  canal  is  still  large. 

The  fourth  vertebra  has  lost  the  upper  part  of  the  neural  arch  and  the  zygapophyses. 
The  transverse  process  (fig.  11  B)  is  curved  outward  and  downward;  the  capitular  process 
is  similar  to  that  of  the  third.  The  lower  face  of  the  centrum  is  concave  antero- 
posteriorly,  but  nearly  flat  transversely.  The  anterior  and  posterior  faces  are  trans- 
versely oval. 


FIG.  10. — Dcstnalosuehus  spurensis. 

A.  Lateral  view  of  first  ten  vertebrae;  the  last  six  as  they  were  found  connected.     X  0.3. 

B.  Upper  view  of  third  to  ninth  cervical  vertebrae.     X  0.3. 

The  next  six  vertebrae  (figs.  10  and  11)  were  found  in  close  association,  the 
first  five  in  position  and  the  sixth  slightly  distant  and  turned  to  one  side.  The  last  is 
thought,  from  its  shape,  to  be  the  twelfth  of  the  whole  series  and  will  be  described  in 
that  position.  In  the  first  five  the  faces  of  the  centra  are  transversely  oval  and  the 
lower  surface  is  flat.  These  characters  change  slowly  toward  the  rear  until  in  the 
tenth  vertebra  (fig.  11)  the  posterior  face  is  nearly  circular  and  the  lower  surface  of 
the  centrum  is  much  narrower  and  longer  than  in  those  anterior  to  it.  The  zygapophyses 
of  all  are  low  and  flat  and  closely  overlapping.  The  posterior  zygapophyses  of  the 
fifth  vertebra  show  clearly  a  structure  which  is  only  indicated  in  the  less  perfectly 
preserved  ones  adjoining  it,  but  is  very  prominent  on  the  second  axis.  From  a  point 
just  above  the  articular  facet  there  is  a  strong  spinous  process  which  extends  backward 
and  outward  for  at  least  a  centimeter.  This  character  is  confined  to  the  anterior 
cervicals,  as  it  is  not  noticeable  on  the  eighth  vertebra,  where  the  zygapophyses  are 
thin  and  broad. 


38 


NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 


The  neural  spine  of  the  fifth  is  low,  thin,  and  broad,  but  posterior  to  this  one  the 
spines  of  the  vertebrae  increase  in  height,  become  thinner  at  the  base,  transversely,  and 
elongate  antero-posteriorly,  and  develop  a  knob  or  expansion  at  the  apex.  The 
transverse  processes  rise  progressively  toward  a  horizontal  position  and  increase  in 
length  and  thickness.  On  the  sixth  vertebra  is  seen  the  beginning  of  a  ridge  running 
from  the  upper  outer  angle  of  the  posterior  face  of  the  centrum  to  the  base  of  the 
transverse  process;  this  continues  to  increase  in  importance  until  on  the  eighth  it  is 
continued  on  to  the  lower  face  of  the  process  as  a  thin  supporting  ridge  inclined  backward, 
and  the  cross-section  of  the  process  is  that  of  a  T-beam.  In  the  same  manner  the 
capitular  process  increases  in  thickness  and  weight,  but  not  in  length.  On  the  ninth 
vertebra  this  process  is  over  a  centimeter  in  its  two  diameters,  and  a  low,  sharp  ridge 
runs  from  its  upper  face  upward  near  the  anterior  face  of  the  centrum,  until  it  joins  the 
ridge  on  the  lower  face  of  the  transverse  process  at  the  level  of  the  base  of  the  neural 
canal. 


FIG.  11. — Desmatosuchus  spurensis. 

A  to  G.  Anterior  views  of  the  third  to  ninth  cervical  vertebrae.     The  figure  of  the  fifth  vertebra  is  slightly 

restored.     X  0.3. 
H.  Posterior  view  of  a  duplicate  tenth  (?)  vertebra,  No.  7504,  U.  of  Mich.     X  0.6. 

In  all  these  vertebra?  the  neural  arch  is  deeply  excavated  between  the  zygapophyses 
both  anteriorly  and  posteriorly,  so  that  a  considerable  portion  of  the  neural  canal  is 
left  uncovered  between  the  vertebrae. 

The  vertebra  posterior  to  the  ninth  were  all  found  isolated,  with  the  exception  of 
the  one  reckoned  as  the  twelfth  and  a  few  in  the  mid-dorsal  region.  They  have  been 
placed  according  to  their  size  and  form.  There  may  be  some  error,  but  it  can  hardly 
be  more  than  one  position. 

In  the  vertebra  reckoned  as  the  tenth  the  zygapophysial  processes  are  broad  and 
thin  and  the  faces  are  nearly  horizontal.  The  transverse  process  is  broad  above;  its 
anterior  edge  is  nearly  on  a  line  with  the  center  of  the  face  of  the  anterior  zygapophyses. 
The  T-section  of  the  process  is  well  developed.  On  this  vertebra  a  ridge  extends  back- 


THE    UPPER   TRIASSIC   OF   WESTERN   TEXAS.  39 

ward  from  the  anterior  upper  angle  of  the  centrum  and  ends  on  the  anterior  face  of  the 
posterior  ridge  as  it  turns  outward  on  the  lower  surface  of  the  transverse  process.  The 
neural  spine  is  elongate  antero-posteriorly.  The  expanded  upper  end  is  wedge-shaped, 
with  the  faces  of  the  wedge  directed  laterally;  the  spaces  between  the  faces  of  the  wedge 
are  roughened.  The  lower  part  of  the  anterior  face  of  the  spine  is  rendered  deeply 
concave  by  the  development  of  ridges  on  each  side,  which  continue  downward  and 
outward  to  end  upon  the  surface  of  the  anterior  zygapophyses.  The  space  between 
these  ridges  and  the  zygapophyses  is  floored  by  a  thin  plate  of  bone  which  covers  the 
neural  canal.  On  the  posterior  face  of  the  spine  there  is  a  similar  development,  but  the 
excavation  of  the  face  of  the  spine  is  much  deeper.  The  faces  of  the  centrum  are  still 
transversely  oval  and  the  lower  surface  flat,  but  the  faces  are  approaching  a  circular 
form  and  the  lower  surface  is  becoming  rounder. 

The  eleventh  vertebra  has  the  transverse  processes  broken  away,  but  the  bases 
are  still  preserved.  The  capitular  face  is  now  elongate  vertically,  and  a  strong  ridge 
runs  from  its  upper  origin,  above  the  level  of  the  base  of  the  neural  canal,  backward 
and  upward  to  join  the  posterior  ridge  which  forms  the  lower  arm  of  the  T-shaped 
transverse  process. 

The  neural  spine  is  elongate  antero-posteriorly  and  thin  transversely.  The  upper 
end  has  a  triangular  expansion  on  each  side,  but  the  ridges  on  the  edges  of  the  anterior 
and  posterior  faces  run  to  the  apex.  The  depression  between  these  ridges  is  similar  to 
that  in  the  preceding  vertebrae;  the  zygapophyses  are  closer  together.  In  the  tenth  and 
eleventh  vertebras  is  seen  for  the  first  time  the  deep  depression  in  the  floor  of  the  neural 
canal.  The  anterior  face  of  the  centrum  is  transversely  oval  and  much  larger  than  the 
posterior  face.  This  is  in  part  due  to  the  development  of  the  capitular  process  with  its 
vertical  extension. 

In  the  twelfth  vertebra  the  capitular  process  rises  from  a  point  above  the  lower 
edge  of  the  centrum,  which  is  now  rounded,  and  is  elongated  vertically,  the  face  being 
nearly  twice  as  high  as  broad.  The  ridge  upon  its  upper  face,  noted  as  beginning  in  the 
eleventh  vertebra,  is  now  developed  as  a  strong  process  which  rises  as  a  wall  and 
is  united  with  the  lower  part  of  the  transverse  process  at  about  the  middle  of  the 
length  of  the  latter.  The  ridge  from  the  posterior  corner  of  the  centrum  is  still 
strong  at  its  origin,  but  has  become  obsolete  on  the  transverse  process  itself;  the 
transverse  process  is  still  T-shaped,  but  the  lower  flange  is  now  formed  by  the  anterior 
ridge  instead  of  the  posterior  one.  In  this  vertebra  the  transverse  plate  between  the 
zygapophyses  has  a  different  form.  From  the  inner  edge  of  each  of  the  posterior  zyga- 
pophyses a  thin  plate  runs  inward  to  form  the  transverse  plate  and  there  is  a  vertical 
extension  downward  in  the  form  of  a  very  thin  septum  which  reaches  to  the  upper  edge 
of  the  neural  canal,  which  is  not  more  than  half  as  large  as  in  the  cervical  vertebras. 
There  is  also  a  tendency  for  a  similar  plate  with  a  vertical  septum  to  form  between 
the  anterior  zygapophyses. 

In  the  thirteenth  vertebra  the  transverse  process  stands  out  directly  from  the  side 
of  the  vertebra  and  rises  slightly  in  its  course,  so  that  the  distal  end  is  higher  than  the 
origin  of  the  process.  The  capitular  face  has  now  left  the  centrum  entirely  and  is  attached 
to  the  transverse  process  at  about  its  middle  portion.  This  face  is  supported  by  three 
ridges — one  very  slender,  running  from  the  lower  edge  of  the  face  to  the  anterior 
upper  angle  of  the  centrum,  the  second  running  from  the  lower  edge  of  the  face  upward 
and  inward  to  the  lower  surface  of  the  base  of  the  anterior  zygapophyses;  the  third 
ridge  is  the  anterior  half  of  the  posterior  ridge.  Its  posterior  half,  so  strong  in  the 
preceding  vertebras,  is  now  obsolescent.  Its  position  marks  the  dividing-line  between 
the  capitular  and  the  tubercular  portions  of  the  transverse  process.  This  sudden  change 
of  position  in  the  capitular  face  is  characteristic  of  the  Crocodilia  and  the  Phytosauria; 


40 


NEW   REPTILES   AND    STEGOCEPHALIANS    FROM 


with  it,  in  the  present  specimen,  begins  the  elevation  of  the  sides  of  the  neural  arch  which 
is  so  notable  in  Desmatosuchus.  The  neural  spine  is  lost,  but  the  space  between  the 
zygapophyses  is  much  narrower.  The  centrum  is  narrower  and  more  elongate,  with 
the  base  rounder  and  the  faces  more  nearly  round. 

From  the  fourteenth  back  to  the  twenty-fourth  (?)  the  vertebrae  are  of  the  true  dorsal 
series  (fig.  12).  The  transverse  processes  increase  to  their  maximum  length  and  are 
inclined  slightly  backward,  the  capitular  faces  gradually  come  to  lie  on  the  anterior 


FIG.  12.— Desmatosuchus  spurensis.     All  figures  X  0.3. 


A.  Anterior  view  of  a  mid-dorsal  vertebra. 

B.  Posterior  view  of  A. 

C.  Lateral  view,  left  side  of  A. 

D.  Upper  view  of  A. 


E.  Lateral  view  of  a  posterior  dorsal  vertebra  with  the 

rib  of  left  side  attached. 

F.  Posterior  view  of  E. 

G.  Upper  view  of  a  posterior  dorsal.     The  broad  apex  is 

broken  off. 


side  of  the  transverse  processes,  and  the  supporting  ridges  become  obsolete  on  the  face 
of  the  elevated  neural  arch.  The  neural  spines  become  more  elongate  antero-posteriorly 
and  the  apex  is  expanded  abruptly  into  a  rounded  rugose  table.  The  centra  become 
elongate  antero-posteriorly,  and  the  edges  of  the  faces  flare  out  so  that  the  lower  face  is 
concave  antero-posteriorly  and  convex  from  side  to  side. 


THE    UPPER   TRIASSIC   OF   WESTERN   TEXAS. 


41 


The  posterior  dorsal  vertebrae  (fig.  12  E  and  F)  become  heavier  in  all  of  their  propor- 
tions; the  spines  remain  thin  transversely,  but  the  apex  becomes  heavier;  the  transverse 
processes  become  shorter  by  the  abbreviation  of  the  distal  end,  so  that  the  capitular 
face  approaches  the  tubercular.  Even  in  the  posterior  dorsals  the  sides  of  the  neural 
arch  remain  elevated  and  the  transverse  processes  take  their  origin  entirely  from  them. 
The  edges  of  the  faces  of  the  centra  are  expanded  so  much  that  a  section  of  the  middle 
of  the  centrum  is  not  more  than  half  as  large  as  that  of  the  faces. 


FIG.  13. — Desmatasuchus  spurensis.    All  figures  X  0.3. 

A.  Posterior  view  of  the  first  true  caudal  vertebra. 

B.  Lateral  view,  left  side  of  A. 

C.  Lateral  view  of  a  median  caudal  vertebra  with  the  incomplete  chevron,  left  side. 

D.  Lower  view  of  C. 

E.  Posterior  (upper)  view  of  the  chevron  shown  in  C. 

The  posterior  presacral  vertebrae  resemble  those  of  the  dorsal  series  in  all  major 
particulars;  the  last  three  or  four  become  decidedly  heavier,  with  larger  centra,  and  the 
transverse  processes  become  broader  antero-posteriorly,  with  the  tubercular  and  capitu- 
lar faces  at  nearly  the  same  distance  from  the  origin  of  the  transverse  process.  The 
ribs  are  lost,  but  there  is  evidence  that  even  to  the  last  the  ribs  were  articulated  with 
the  transverse  process  and  not  reduced  and  coossified  with  them;  in  this  sense  there  are 
no  true  lumbars. 

A  single  very  poorly  preserved  vertebra  which  seems  to  have  a  very  heavy  neural 
spine  and  a  short,  heavy  transverse  process,  or  origin  of  a  sacral  rib,  may  be  regarded  as 
one  of  the  sacrals.  This  region  is  in  poor  condition;  only  a  portion  of  a  very  poorly 
preserved  half  of  the  pelvis,  as  noted  below,  is  preserved. 


42 


NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 


There  are  six  caudals  preserved,  all  chevron-bearing  (fig.  13).  It  is  probable 
that  there  were  two  or  three  pygal  vertebrae  present.  In  the  caudals  preserved  the  trans- 
verse process  springs  from  the  side  of  the  neural  arch  and  curves  outward  and  down- 
ward, becoming  thin  and  more  horizontal  toward  the  distal  end.  The  zygapophyses 
are  well  developed,  with  the  faces  nearly  flat;  the  characteristic  recess  continues  at 
the  base  of  the  neural  spine,  but  with  the  decrease  in  height  of  the  neural  arches  the 
median  descending  vertical  plate  between  the  zygapophyses  disappears.  The  first 
three,  which  are  evidently  anterior  caudals,  have  heavy  spines  with  thickened  apices. 
The  lower  face  of  the  centrum  is  marked  by  a  median  depression  which  separates  two 
strong  ridges  on  the  sides;  these  terminate  posteriorly  in  the  faces  for  the  chevrons, 
which  look  more  downward  than  backward. 


FIG.  14. — Desmatosuchus  spurensis.    All  figures  X  0.3. 

A.  Upper  surface  of  the  seventh  (?)  rib  of  the  left  side. 

B.  Lower  view  of  A. 

C.  Lower  view  of  tenth  rib,  left  side. 

D.  Upper  view  of  B. 

E.  Upper  view  of  eleventh  rib,  right  side. 

F.  Lower  view  of  E. 

The  last  two  caudals  (fig.  13  c  and  D)  are  in  poor  condition,  due  to  decay,  but  are 
more  elongated  than  the  anterior  ones,  and  there  is  a  decided  tendency  for  the  posterior 
faces  to  descend  lower  than  the  anterior  ones. 

The  chevron  bones  (fig.  13  A  and  E)  are  widely  separated  at  the  proximal  end,  but 
meet  in  a  strong  terminal  portion.  The  exact  length  is  not  shown  in  any  one. 

The  ribs. — There  were  free  ribs  on  all  of  the  vertebrae  of  the  presacral  series,  but 
the  posterior  ones  show  a  strong  tendency  to  a  close  anchylosis  with  the  transverse 
process.  Those  of  the  cervical  series  were  small  and  turned  back  close  to  the  side  of 
the  vertebrae,  as  is  evidenced  by  the  small  amount  of  space  between  the  vertebrae  and 
the  sides  of  the  dorsal  armor.  The  first  rib  preserved  was,  in  all  probability,  attached 
to  the  seventh  vertebra,  as  it  was  found  close  to  it  and  fits  the  articulations  quite  closely. 
This  rib  (fig.  14  A  and  B)  is  still  short,  and  the  capitular  and  articular  processes  are 
nearly  equal  in  length.  The  dorsal  surface  of  the  rib  is  expanded  into  a  broad,  thin 
surface,  which  is  supported  by  a  thin,  high  ridge  running  the  length  of  the  rib  on  the 
under  side;  this  ridge  has  its  origin  on  the  tubercular  process. 


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THE   UPPER   TRIASSIC   OF   WESTERN   TEXAS. 


43 


The  second  well-preserved  rib  is  assigned  to  the  tenth  vertebra  (fig.  14  c  and  D). 
It  is  much  longer  than  the  seventh  and  the  tubercular  process  is  much  shorter  than  the 
capitular.  There  is  still  some  expansion  of  the  upper  surface,  though  much  less  than 
in  the  ribs  anterior  to  it.  Traces  of  the  supporting  ridge  on  the  lower  side  are  still 
present. 

The  third  well-preserved  rib  is  assigned  to  the  eleventh  vertebra  (fig.  HE  and  F). 
This  closely  resembles  the  rib  assigned  to  the  tenth,  but  is  even  longer,  and  the  expan- 
sion of  the  upper  surface  is  more  closely  confined  to  the  proximal  end.  The  capitular 
and  tubercular  faces  are  close  together,  corresponding  to  the  approximation  of  the  facets 
upon  the  vertebrae. 

A  fourth  well-preserved  rib  is  assigned  to  the 
twelfth  vertebra  (fig.  15).  This  rib  is  much  stronger 
than  the  preceding  ones  and  longer.  The  whole  rib  is 
flat  and  rather  thin.  The  capitular  process  and  face 
are  stronger  than  on  the  anterior  ribs  and  the  tuber- 
cular face  is  located  as  a  notch  on  the  body  of  the 
rib.  This  is  the  first  rib  that  shows  any  decided  down- 
ward curvature  of  the  shaft. 

In  the  following  ribs,  which  are  only  incompletely 
preserved,  the  tubercular  and  capitular  faces  are  on 
the  same  plane;  the  ribs  are  relatively  broad  in  the 
dorsal  series,  with  a  considerable  outward  extent,  indi- 
cating a  well-rounded  barrel  in  the  animal.  In  the  pos- 
terior dorsal  and  lumbar  (?)  regions  the  ribs  become 
shorter  and  more  slender;  the  capitular  and  tubercular 
faces  gradually  approximate  until  they  are  nearly  on 
a  line. 

The  dermal  armor  (plates  8  and  9). — The  back 
of  Desmatosuchus  was  covered  by  a  complete  armor 
consisting  of  four  rows  of  plates.  The  presence  of  any 
lateral  or  abdominal  armor  is  uncertain.  Aside  from  the  presumption  that  such  plates 
occurred,  there  is  a  single  small,  irregular  plate  which  was  found  intimately  associated 
with  the  rest  of  the  armor  and  skeleton. 

The  dorsal  armor  consists  of  four  rows  of  plates  arranged  symmetrically  in  succes- 
sive transverse  series.  The  two  inner  rows  are  composed  of  flat  plates  with  a  small 
subcentral  knob;  these  plates  increase  in  breadth  toward  the  dorsal  region,  at  the  same 
time  decreasing  in  their  antero-posterior  extent.  The  outer  rows  are  composed  of  plates 
which  have  the  two  sides  of  the  bases  bent  almost  at  right  angles  to  each  other,  so  that 
a  portion  lies  over  the  back  and  a  portion  over  the  sides;  they  bear  spines  which  are  of 
varying  height  in  the  different  parts  of  the  body.  It  is  probable  that  the  median  rows 
disappeared  in  the  posterior-caudal  region,  but  of  this  there  is  no  direct  evidence.  It 
will  be  best  to  describe  the  plates  according  to  the  transverse  series.  The  general 
arrangement  is  shown  in  the  plates  and  figures.  The  transverse  series  of  dorsal  plates 
begins  immediately  behind  the  skull,  but  the  anterior  ones  are  not  arranged  in  relation 
to  the  vertebrae  below;  the  first  five  series  of  plates  cover  the  entire  cervical  series  of 
vertebrae. 

The  plates  of  the  first  series  are  represented  by  the  lateral  one  from  the  right 
side;  it  is  incomplete,  but  shows  a  decided  spine. 

The  second  scries  is  represented  by  the  median  plate  of  the  left  side  and  the  two 
lateral  plates.  In  common  with  all  the  plates  of  the  cervical  region,  the  median  plates 
were  quite  thick  on  the  inner  and  outer  edges  and  thin  on  the  anterior  and  posterior 


FIG.  15. — Desmatosuchus  spurensis. 

A.  Lower  view  of  the   twelfth   rib,   left 

side.     X  0.3. 

B.  Upper  view  of  A. 


44 


NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 


edges.  The  low  knob  is  nearer  to  the  posterior  corner  of  the  plate  (fig.  16  A).  The 
anterior  edge  is  the  broader  and  the  outer  edge  slopes  backward  and  inward  to  the  pos- 
terior edge.  The  left  plate  of  the  outer  row  of  this  series  is  nearly  complete.  The 
inner  edge  is  thickened  to  form  a  firm  union  with  the  inner  plate;  the  outer  edge  is  thinner 
and  slopes  backward  and  outward  to  the  broader  posterior  edge.  The  spine  is  located 
on  the  outer  half  of  the  plate  and  is  inclined  outward  and  slightly  backward.  The 
anterior  surface  of  the  spine  is  drawn  out  into  a  narrow,  sharp  edge  which  slopes  forward 
to  the  middle  of  the  plate. 


FIG.  16. — Desmalosuchus  spurensis,  dorsal  armor  of.     All  figures  X  0.3. 

A.  Upper  view  of  median  plate  of  second  series,  right  side. 

B.  Upper  view  of  median  plate  of  the  third  series,  left  side. 

C.  Upper  view  of  the  two  median  plates  of  the  fifth  series. 

D.  Anterior  view  of  the  right  side  of  C. 

E.  Inner  (upper)  view  of  the  lateral  plate  of  the  third  series,  left  side. 

F.  Posterior  view  of  E. 

The  third  series  has  the  plates  (fig.  16  B)  nearly  complete.  The  median  plates 
are  similar  to  the  second,  except  that  they  are  proportionately  larger.  It  is  clear  in  this 
series  that  the  plates  overlap  to  the  rear,  and  this  is  continuous  throughout  the  series. 
There  is  little,  or  a  very  fine,  sculpture.  The  outer  plates  have  high  spines  located 
near  the  posterior  edge,  with  a  thin  flange  extending  down  the  anterior  side.  This  is 
shown  in  figure  16  A  and  B.  The  two  parts  of  each  plate  lie  nearly  at  right  angles 
to  each  other.  The  inner  edge  is  thickened  for  articulation  with  the  median  plate, 
while  the  outer  part  is  thin  and  larger.  The  anterior  edge  is  narrower,  but  the  outer 
edge  slopes  backward  and  outward  to  meet  the  broader  posterior  edge.  The  outer  side 
shows  the  beginning  of  a  rough  sculpture  of  relatively  small  pits  and  ridges.  When 
in  position  the  spines  point  outward  and  a  little  upward. 

The  fourth  series  is  represented  by  the  conjoined  plates  of  the  left  side  and  an 
imperfect  median  plate  of  the  right  side.  The  left  plates  are  complete,  except  for  the 
extremity  of  the  spine.  The  median  plates  are  similar  to  those  preceding,  but  are 
larger.  The  outer  plate  carries  a  heavy  spine,  of  which  the  lower  half  only  is  preserved. 
The  inner  side  of  the  spine  is  nearly  flat,  but  there  is  a  thin,  strong  ridge  on  the  anterior 
side.  As  in  the  preceding  plates,  the  anterior  edge  is  shorter  than  the  posterior,  and  the 
outer  edge  slopes  backward  and  outward.  Both  the  inner  and  the  outer  plates  show  an 
increase  in  the  size  of  the  sculpture,  which  becomes  so  heavy  and  rough  in  the  dorsal 
region. 


CASE 


PLATE  9 


T1IK    UPPER    TRIASSIC   OF   WESTERN   TEXAS.  45 

The  fifth  series  is  represented  by  two  complete  median  plates  (fig.  16  c  and  D),  the 
complete  plate  of  the  outer  row  of  the  left  side  and  an  incomplete  spine  of  the  right  side. 
The  median  plates  are  similar  to  the  preceding  plates.  The  outer  plates  present  the  most 
remarkable  feature  of  the  armor.  Each  one  bears  an  enormous  spine,  over  45  centimeters 
in  length;  this  extends  almost  directly  outward,  but  a  little  upward,  and  from  its  middle 


FIG.  17. — Desmatosuchiu  spurengis. 

A.  Lower  (outer)  view  of  the  lateral  plate  of  the  fifth  series  in  the  dorsal  armor, 

left  side.     X  0.3. 

B.  Posterior  view  of  A. 

point  curves  backward  as  far  as  the  middle  of  the  seventh  series  of  plates  (fig.  17).  The 
base  of  the  spine  is  flattened  on  its  inner  and  anterior  side,  but  is  rounded  on  the  outer 
side.  The  angle  between  the  inner  and  anterior  faces  is  continued  to  about  the  middle 
of  the  spine  and  then  disappears,  the  section  then  becoming  circular,  which  continues 
to  the  acute  distal  extremity.  The  base  of  the  plate  is  actually  larger  than  the  preceding 
ones,  but  relative  to  the  spine  much  smaller;  the  inner  edge  is  thickened  for  attachment 
to  the  median  plates;  the  outer  edge  is  thin  and  the  anterior  and  posterior  edges  are 
of  about  equal  width. 

The  accurate  fit  of  the  plates  of  this  row  permits  a  determination  of  the  outline 
of  the  armor  at  this  point,  and  this  is  checked  by  the  conjoined  plates  of  the  fourth  ring 
(see  plate  8  E  to  H).  This  is  most  fortunate,  as  the  position  and  attitude  of  the  spine 
would  hardly  be  credible  otherwise.  The  position  of  the  great  spine  curving  outward 
and  backward  could  hardly  have  been  imagined,  and  its  meaning  is  still  a  puzzle. 

Posterior  to  the  fifth  series  the  armor  becomes  flat  and  broad  and  descends  but  a 
short  distance  on  the  sides.  The  plates  of  the  median  row  rapidly  contract  antero- 


46 


NEW   REPTILES   AND    8TEGOCEPHALIANS   FROM 


posteriorly  and  broaden  transversely  through  the  sixth,  seventh,  and  eighth  rows,  and 
by  the  ninth  they  have  reached  the  normal  form  of  the  dorsal  series,  which  continues 
back  nearly  to  the  sacral  region.  The  low  spine  or  knob  is  located  a  little  outside  of 
the  center  and  is  directed  backward  and  inward.  The  plates  are  covered  by  a  rough 
sculpture,  shown  in  figure  18  c,  which  extends  to  the  thin  edges  except  for  about  1  or  1.5 
centimeters  on  the  anterior  edge.  This  smooth  area  on  the  edge  of  the  plate  indicates  an 
overlapping,  but  it  must  have  been  very  slight  in  the  dorsal  region.  Examination  of  the 
plates  in  the  armor  of  several  species  of  alligators,  crocodiles,  and  caimans  shows  that  there 
is  no,  or  very  slight,  overlapping  of  the  plates  in  any  of  these  forms,  and  that  it  occurs  only 
in  an  overflexion  of  the  back.  The  same  smooth  area  appears  on  some  of  the  plates 
in  these  living  forms  and  seems  to  be  a  region  of  attachment  of  tough  skin  or  tendinous 
material.  The  outer  plates  have  low,  sharp  spines,  which  are  broader  antero-posteriorly 
in  the  sixth  and  seventh  rows,  but  of  nearly  equal  diameters  in  the  ninth  and  following 
ones.  The  spines  were  inclined  outward  and  a  little  backward.  The  inner  half  of  the 
base  is  shorter  than  the  outer.  The  inner  half  is  nearly  horizontal  and  the  outer  half  is 
nearly  vertical,  but  inclined  a  little  outward.  There  is  evidence  from  one  side  or  the 
other  of  17  plates  of  this  kind,  making  at  least  9  rows  in  the  mid-dorsal  series. 


FIG.  18. — Desmatosuchus  spurensis. 

A.  Median  plate  of  a  mid-dorsal  series.     X  0.3. 

B.  Outer  view  of  a  lateral  plate  of  a  caudal  series,  left  side.      X  0.3. 

C.  Posterior  view  of  B. 

Posterior  to  the  plates  of  the  dorsal  series  there  are  no  representatives  of  the  median 
plates,  but  there  is  a  considerable  number  of  plates  from  the  outer  series.  They  differ 
notably  from  those  of  the  prepelvic  region  (fig.  18s  and  c).  The  outer  half  of  the  base  is 
much  longer  than  the  inner,  and  is  in  the  same  plane  with  the  outer  sides  of  the  spines. 
This  character  becomes  more  noticeable  as  the  plates  become  smaller,  that  is,  in  the  pos- 
terior part  of  the  caudal  series.  The  spines  are  relatively  higher  than  in  the  dorsal  series. 
The  sculpture  becomes  less  rough  in  the  posterior  plates.  It  is  believed  that  in  the 
distal  portion  of  the  tail  the  median  row  disappeared,  as  it  does  in  the  Crocodilia. 

The  scapula-coracoid. — With  the  skeleton  was  found  the  distal  end  of  a  scapula- 
coracoid  so  radically  different  from  the  usual  form. found  in  the  Phytosauria  that  it  is 
difficult  to  reconcile  it  with  the  vertebral  column,  but  it  is  no  more  peculiar  than  the  skull. 
It  does,  however,  resemble  very  closely  the  scapula-coracoid  of  Stagonolepis.  The 
cotylus  is  large  and  cleanly  formed  and  is  somewhat  obliquely  placed  in  the  bone.  The 
upper  edge  overhangs  strongly;  the  lower  edge  is  broken  away.  A  ridge  interrupting 
the  smooth  face  of  the  articular  surface  is  perhaps  due  to  pressure,  but  seems  normal. 
Just  anterior  to  the  edge  of  the  cotylus  is  a  pit  which  seems  to  belong  to  the  bone  and 
not  due  to  the  action  of  decay  and  gypsum.  The  coracoid  foramen  is  at  about  the  level 
of  the  lower  edge  of  the  cotylus  and  perforates  the  bone  upward  and  inward;  on  the 
posterior  side  the  opening  of  the  foramen  is  directly  upward.  On  the  anterior  edge 


CASE 


PLATE  10 


5 
ti 

8 


t-c    a 
c,    o 


S 

O. 


2 


I  d 

^o 

"5 


— 
t* 
_o 

*n 

a 


THE    UPPER   TRIASSIC    OF   WESTERN   TEXAS. 


47 


opposite  the  upper  edge  of  the  cotylus  there  is  a  decided  prominence;  below  this  the 
edge  of  the  bone  is  quite  thin.  The  lower  and  anterior  edges  of  the  coracoid  have  been 
injured  by  decay,  but  could  not  have  had  a  very  much  greater  extent. 

Measurements  of  Desmatosuchus. 


Length  of  skull  on  right  side 27.4 

Width  of  skull  :it  [xistc/ior  end 16.4 

Length  of  axis  and  atlas  at  base 7.6 

Length,  anteiior  end  of  skull  to  first  sacral I'.'N  *> 

Length  of  large  spine  along  outside  curve 39.4 


Same  with  extreme  tip,  now  lost,  added 40.9 

Extent  of  long  spine  from  mid-line 41 .2 

Average  length  of  mid-dorsal  plate 16.8 

Average  length  of  same,  antero-pMterior 8.4 


The  restoration  (fig.  20). — In  the  attempted  restoration  consideration  has  been 
given  to  several  factors.  It  is  obvious  that  such  an  animal  as  Desmatosuchus,  with  its 
spiny  armor,  would  have  considerable  difficulty  in  making  progress  through  tangled 
vegetation,  either  aquatic  or  terrestrial,  and  it  is  in  accord  with  this  character  and  the 
suggestion  of  the  sediments  that  sparse  vegetation  and  open  water  are  indicated  in  the 
environment.  It  must  be  remembered 
in  considering  the  nature  of  the  animal 
that  its  remains  are  very  limited  in 
quantity  in  a  region  where  the  remains 
of  Phytosaurs  are  relatively  abundant. 
It  would  appear  that  Desmatosuchus 
inhabited  a  region  somewhat  different 
from  that  occupied  by  Belodon  and 
Mystriosuchus,  either  more  remote  from 
the  pools  which  formed  the  favorable 
environment  of  more  common  forms  or 
a  region  geographically  remote  from 
the  locality  where  the  collection  was 
made.  It  is  exceedingly  unfortunate 
that  no  teeth  were  found  with  the 
specimen,  and  so  no  more  than  a  guess 
can  be  made  of  the  nature  of  its  food; 
but  as  the  sockets  are  simp  e  and 
rounded,  it  is  safe  to  assume  the  teeth 
were  single  cones  and  that  the  animal 
was  carnivorous.  Inhabiting  an  area  of 
open  land,  it  is  probable  that  the  animal  must  have  had  relatively  long  limbs,  a  prob- 
ability borne  out  by  the  size  of  the  pelvis  and  the  shape  of  the  acetabulum,  and  further 
by  the  facts  that  no  short  limb-bones  were  found  in  the  locality  and  that  the  frag- 
ment of  the  shaft  of  a  limb-bone  found  with  Desmatosuchus  is  evidently  part  of  a  long 
femur  or  humerus.  No  trace  of  the  feet  or  claws  was  found,  and  the  suggestion  of  par- 
tially webbed  feet,  implying  a  dominantly  aquatic  habitat,  may  be  erroneous.  The 
weight  of  the  great  carapace  would,  perhaps,  also  be  an  objection  to  the  assumption  of  an 
aquatic  life.  For  the  same  reason — the  possibility  that  the  habitat  was  not  dominantly 
aquatic — it  is  possible  that  the  tail  has  been  made  too  long  and  too  much  of  a  swimming 
organ. 

Critical  study  of  the  specimen  in  the  course  of  mounting  the  skeleton  has  led  to 
the  conclusion  that  the  plates  of  the  dorsal  armor  did  not  overlap  when  the  animal  was 
in  a  normal  position,  but  overextension,  as  by  a  strong  upward  curvature  of  the  body, 
would  have  been  possible  only  by  the  overlapping  of  the  plates.  This  is  the  condition 
found  in  the  modern  Crocodilia. 


FIG.  19. — Desmatosuchus  spurensis. 

A.  Anterior  view  of  the  distal  portion  of  the  scapula-coracoid' 

right  side.      X  0.3. 

B.  Outer  view  of  A.     X  0.3. 


48 


NEW    REPTILES   AND    STEGOCEPHALIANS   FROM 


The  relationships  of  Desmatosuchus. — To  the  author  it  seems  apparent  that  Des- 
matosuchus can  be  considered  only  as  a  member  of  a  branch  of  the  Parasuchian  stem 
which  has  developed  a  high  degree  of  specialization.  The  character  of  the  vertebral 
column  and  the  carapace  indicates  close  relationships  to  the  Parasuchia;  all  the  remarkable 
features  of  the  carapace  are  simple  developments  of  possibilities  clearly  indicated  in  the 
more  conservative  line. 

.1 


FIG.  20. — Restoration  of  Desmatosuchus  spurensis. 

It  is  in  the  skull  that  the  morphological  divergence  from  the  line  of  the  Parasuchia 
is  clearly  evident.  The  author,  as  indicated  in  the  body  of  the  description,  is  unable  to 
accept  the  suggestion  made  by  Doctors  Huene  and  Watson  that  the  single  large  temporal 
opening  is  the  upper  and  that  the  bones  outlining  the  lower  opening  have  been  lost. 
Reasons  for  this  opinion  have  been  given  in  detail  in  a  preceding  portion  of  this  article. 
The  single  temporal  opening  and  the  amazing  condition  of  the  quadrate  region  clearly 
place  the  animal  in  a  separate  suborder  or  even  order.  The  basicranial  region,  the 
antorbital  opening,  and  the  lack  of  a  pineal  foramen,  together  with  the  character  of  the 
vertebral  column  and  the  carapace,  just  as  clearly  indicate  affinities  with  the  Parasuchia. 
Until  future  discoveries  shall  prove  the  author's  interpretation  of  the  skull  to  be  erro- 
neous, or  shall  reveal  further  structures  which  will  make  more  evident  the  affinities  of 
the  animal,  Desmatosuchus  must  be  considered  as  a  member  of  a  distinct  order  or  suborder 
of  phytosauroid  reptiles,  highly  specialized  in  its  morphology  and  confined  to  the  Upper 
Triassic  of  North  America. 


CASE 


PLATE  II 


if 

X    * 


-r    i 

•  —        V. 

§1 


-s_ 

*l 

z  5 

j  H 
J  j 


II 

- 


-    - 
-=    = 


- 

00 


e  ^ 

-  — 

-  - 


THE   UPPER   TRIASSIC   OF   WESTERN    TEXAS.  49 

A  NEW   PARASUCHIAN,   PROMYSTRIOSUCHUS  EHLERSI. 

The  specimen  (No.  7487,  University  of  Michigan)  described  below  was  discovered 
by  the  author  in  a  bed  of  yellowish  sandy  clay  near  the  head  of  Holmes  Creek,  Crosby 
County,  Texas,  in  the  summer  of  1921.  The  patch  of  sandy  clay  is  but  a  minor  phase 
of  the  larger  deposit  in  which  so  many  remains  of  reptiles  and  amphibians  occur  in  this 
locality.  Near  the  specimen,  and  in  the  same  kind  of  matrix,  occur  large  numbers  of 
fragmentary  bones,  teeth,  and  coprolites.  This  small  patch  is  evidently  a  bit  of  an  old 
sand-bar,  or  an  accumulation  of  sandy  clay  in  some  small  depression  which  has  been 
well  leached  by  percolating  waters.  The  relatively  small  percentage  of  clay  rendered 
the  matrix  easily  permeable  by  the  waters  which  converted  the  iron  into  limonite  and  in 
spots  removed  it  so  completely  that  the  matrix  is  pure  white;  in  other  spots  the  matrix 
is  still  purple  from  the  unchanged  iron  of  the  original  deposit.  The  limonite  was  con- 
centrated upon  the  bones,  covering  them  with  a  thin  scale,  and  was  deposited  in  the 
cracks  between  the  pieces  of  the  broken  bones.  Movements  in  the  ground  crushed  the 
skull  and  broke  it  into  many  small  pieces  which  are  slightly  displaced.  The  cleaning 
and  restoration  were  rendered  difficult  by  the  distortion  and  breaking  of  the  bones,  but 
as  the  fragments  were  only  slightly  displaced  it  was  possible  to  harden  the  matrix  or 
replace  it  by  plaster  cement  and  work  out  the  original  form  of  the  skull.  The  anterior 
half  of  the  long  rostrum  was  weathered  out,  but  it  has  been  possible  to  fit  the  pieces  into 
place  and  determine  very  accurately  the  length  and  form  of  the  nose.  From  the  narial 
opening  forward,  the  two  halves  of  the  skull  were  separated  slightly;  the  palate  was 
crushed  and  pushed  somewhat  toward  the  left  side.  The  posterior  part  of  the  lower  jaw 
of  the  left  side  was  recovered,  but  the  anterior  end  was  destroyed  by  decay  before 
fossilization. 

Because  of  the  fractured  and  compressed  condition  of  the  skull,  it  is  intelligible 
only  after  considerable  study;  the  figures  presented  are  restorations  which  have  been 
made  with  as  great  accuracy  as  possible,  being  the  result  of  six  different  attempts,  made 
as  checks,  and  are,  in  the  opinion  of  the  author,  very  satisfactory  representations  of  the 
original  condition.  The  location  of  the  sutures  was  rendered  difficult  by  the  innumerable 
cracks  and  the  condition  of  the  specimen;  only  those  that  have  been  determined  with 
certainty  are  represented  in  solid  line. 

The  peculiar  characteristics  of  the  specimen  are  the  slight  extension  of  the  squamosal 
region  behind  the  occipital  condyle,  the  elevated  position  of  the  parieto-squamosal  arch, 
the  absence  or  small  size  of  the  post-temporal  opening,  the  very  long  parasphenoid 
process,  and  the  large  interpterygoid  space.  The  lack  of  any  great  posterior  extension 
of  the  squamosal  region,  the  great  length  of  the  parasphenoid,  and  the  large  interpterygoid 
space  are  primitive  characters  recalling  the  condition  in  Mesorhinus,  but  the  development 
of  the  external  process  of  the  pterygoids,  the  character  of  the  transverse,  the  shape  and 
condition  of  the  palatines,  and  the  elongate  rostrum  are  features  belonging  to  the  more 
highly  specialized  of  the  Phytosaurs  of  the  Upper  Triassic.  The  suggestion  of  immaturity 
conveyed  by  the  small  size  of  the  skull  is  not  borne  out  by  the  condition  of  the  bones 
and  the  sutures.  It  is  evident  that  we  have  to  do  with  a  fully  mature  Phytosaur  of  the 
Mystriosuchid  group,  of  small  size  and  distinct  in  its  characters  from  any  previously 
described. 

The  upper  surface  of  the  skull  (plate  11,  fig.  A). — The  openings  in  the  skull:  The 
supratemporal  openings  are  elongate  oval  and  lie  entirely  upon  the  upper  surface  of  the 
skull;  their  boundaries  are  shown  in  the  figures.  The  orbits  are  somewhat  oval  in  outline 
and  lie  almost  entirely  upon  the  surface;  the  lateral  presentation  is  very  slight.  The 
narial  opening  is  entirely  upon  the  upper  surface  and  is  surrounded  by  an  elevated 
rim;  it  is  divided  somewhat  deeply  below  the  rim  by  a  pair  of  small  bones  which  are 


50  NEW    REPTILES   AND    STEGOCEPHALIANS   PROM 

described  below.  The  lateral  temporal  openings  are  elongate  and  inclined  downward 
and  forward,  reaching  as  far  forward  as  the  center  of  the  orbit.  The  antorbital  openings 
are  elongate  and  rather  narrow  vertically;  they  reach  from  just  anterior  to  the  orbit 
to  a  point  below  the  center  of  the  narial  opening.  Both  the  lateral  temporal  openings 
and  the  antorbital  openings  are  but  partially  visible  from  above. 

The  parietal  bones  are  small,  each  with  a  slender  process  extending  outward  and 
backward  and  forming  the  upper  edges  of  the  deep  notch  at  the  posterior  end  of  the 
skull.  These  processes  form  the  inner  borders  of  the  upper  temporal  openings  and  ter- 
minate near  its  posterior  end.  The  anterior  portion  of  each  parietal  meets  its  fellow  of 
the  opposite  side  in  the  median  line;  the  extent  forward  is  not  accurately  made  out,  but 
it  is,  in  all  probability,  not  great.  This  portion  of  the  parietal  forms  the  anterior  edge 
of  the  upper  temporal  opening.  There  is  no  trace  of  a  parietal  foramen. 

The  squamosals  are  cruciform  in  outline.  The  anterior  arm  unites  with  the  postor- 
bital  to  form  the  bar  between  the  two  temporal  openings.  The  inner  arm  is  very  narrow 
and  unites  with  the  parietal;  the  outer  arm  is  much  wider  and  is  overlapped  by  the  upper 
end  of  the  quadratojugal.  On  the  lower  surface  of  this  arm  there  is  a  concave  surface, 
elongate  laterally  for  the  reception  of  the  upper  end  of  the  quadrate;  this  is  clearly  shown 
on  the  left  side,  where  the  quadrate  is  missing,  having  been  lost  by  maceration  before 
the  fossilization  of  the  skull.  The  posterior  arm  is  short;  its  upper  surface  is  marked 
by  prominent  rugose  ridges  extending  in  the  direction  of  the  greatest  length  of  the  bone. 
The  posterior  end  overhangs  the  distal  end  of  the  opisthotic. 

The  postorbital  forms  a  small  part  of  the  posterior  edge  of  the  orbit  and  articulates 
with  the  jugal  below.  It  sends  backward  and  slightly  outward  a  broad  arm  which  unites 
with  the  squamosal.  Just  anterior  to  the  suture  there  is  a  broadening  of  the  outer  side 
which  forms  a  constriction  in  the  lateral  temporal  foramen. 

The  outlines  of  the  frontals,  postfrontals,  prefrontals,  and  nasals  can  not  be  made 
out  clearly.  This  portion  of  the  skull  is  rugose  and  is  badly  broken  and  cracked,  the 
cracks  being  filled  with  limonite,  so  that  the  sutures  can  not  be  followed.  The  probable 
course  of  the  various  sutures  is  indicated  in  dotted  lines  in  the  figures.  It  seems  alto- 
gether probable  that  the  nasals  had  considerable  extent  posterior  to  the  narial  opening. 
Dividing  the  narial  opening  some  distance  below  the  upper  edge  of  the  rim,  there  is  a 
slender  rod  formed  by  two  narrow,  elongate  bars  which  meet  in  a  close,  relatively  broad 
symphysis,  as  shown  in  figure  21.  This  septum  is,  in  all  probability,  formed  by  the 
anterior  ends  of  the  nasals. 

The  septomaxillaries. — No  trace  of  these  elements  could  be  found,  but  it  may  well 
be  that  the  limiting  sutures  are  obscured  in  the  specimen. 

The  premaxillaries  form  the  greater  part  of  the  long,  slender  rostrum  anterior  to 
the  narial  opening.  The  origin  of  the  maxillary-premaxillary  suture  lies  about  3  centi- 
meters in  advance  of  the  opening ;  the  suture  is  traceable  backward  between  the  two  bones 
and  then  is  apparently  continued  backward  between  the  premaxillaries  and  the  nasals, 
allowing  the  premaxillaries  to  take  a  small  part  in  the  anterior  portion  of  the  rim  of  the 
nares;  this  last  point  is,  however,  uncertain.  The  anterior  ends  of  the  premaxillaries 
are  only  very  slightly  thickened  and  expanded  to  accommodate  the  alveoli  of  the  anterior 
teeth.  The  rugosity  of  the  upper  surface  terminates  with  the  narial  opening  and  the 
surface  of  the  maxillaries  and  premaxillaries  is  relatively  smooth.  The  quadratojugal,  jugal, 
maxillary,  and  lachrymal  are  only  obliquely  and  imperfectly  exposed  in  the  upper  view. 

The  side  of  the  skull  (plate  11,  fig.  B). — The  small  extent  of  the  projection  of  the 
squamosal  beyond  the  quadrate  and  occipital  condyle  is  very  noticeable  in  this  view. 
The  posterior  process  of  the  squamosal  is  excavated  below,  so  that  the  whole  projection 
is  thin  and  without  a  terminal  descending  portion.  In  the  notch  below  can  be  seen  the 
distal  extremity  of  the  opisthotic. 


THE    UPPER   TRIASSIC    OF   WESTERN   TEXAS.  51 

The  quadratojugal  is  high  behind,  forms  the  posterior  edge  of  the  lateral  face  of 
the  skull,  and  conceals  the  quadrate.  Its  upper  anterior  edge  forms  the  posterior  half 
of  the  lower  edge  of  the  lateral  temporal  opening.  Its  lower  edge  forms  the  extreme 
posterior  part  of  the  lower  edge  of  the  skull,  but  is  soon  covered  by  the  jugal;  the  suture 
between  these  two  bones  passes  obliquely  upward  and  forward. 

The  jugal  forms  the  lower  edge  of  the  skull  as  far  forward  as  the  anterior  end  of  the 
lateral  temporal  opening;  it  is  then  covered  by  the  maxillary  and  the  suture  between 
them  runs  forward  and  upward,  terminating,  apparently,  on  the  lower  edge  of  the  antor- 
bital  opening,  about  one-third  of  the  length  of  the  edge  from  the  posterior  end.  The 
jugal  is  deeply  notched  posteriorly  by  the  anterior  end  of  the  lateral  temporal  opening 
and  forms  both  the  upper  and  lower  edges  of  this  part  of  the  opening.  The  suture 
between  the  jugal  and  the  postorbital  lies  at  the  posterior  end  of  the  orbit  and  the  jugal 
forms  much  of  the  outer  orbital  rim.  The  suture  between  the  jugal  and  the  lachrymal 
can  not  be  made  out. 

The  lachrymal  can  not  be  delimited  with  certainty;  it  probably  occupies  the  same 
position  as  in  most  of  the  Phytosauria  and  forms  the  posterior  border  of  the  antorbital 
opening. 

The  maxillary  starts  from  a  point  below  the  anterior  edge  of  the  lateral  temporal 
opening  and  forms  the  lower  edge  of  the  skull  as  far  forward  as  about  3  centimeters  in 
front  of  the  narial  opening.  Its  upper  edge  forms  the  anterior  two-thirds  of  the  lower 
border  of  the  antorbital  opening.  A  thin  groove,  which  apparently  marks  the  position 
of  a  suture,  rises  from  the  middle  of  the  upper  border  of  the  antorbital  opening  and  runs 
forward  close  to  the  edge;  it  is  traceable  out  upon  the  face  of  the  skull  for  some  distance; 
it  apparently  joins  the  suture  between  the  maxillary  and  the  premaxillary.  It  is  believed 
that  this  groove  marks  the  position  of  the  suture  between  the  maxillary  and  the  nasal, 
as  the  form  of  the  maxillary  thus  outlined  is  found  in  several  genera  of  the  Phytosaurs. 

The  nasals  can  not  be  exactly  outlined.  If  the  suture  described  above  is  correctly 
determined,  the  nasals  form  most  of  the  sides  of  the  skull  above  the  antorbital  opening, 
form  a  part  of  its  upper  border,  and  join  the  lachrymals  and  prefrontals  posteriorly. 
Anteriorly  the  nasals  probably  form  the  borders  of  the  narial  opening,  except,  possibly, 
the  median  portion  of  the  anterior  edge,  and  send  slender  processes  forward  between 
the  maxillaries  and  the  premaxillaries.  The  septum  in  the  narial  opening  is  in  all  proba- 
bility formed  by  the  nasals. 

The  premaxillaries. — The  outline  of  the  posterior  end  of  the  premaxillaries  is  uncer- 
tain, but  they  apparently  send  long  processes  backward  and  upward  which  terminate  in 
the  anterior  median  portion  of  the  edge  of  the  narial  opening  and  join  the  nasals  and 
maxillaries.  Anteriorly  they  form  the  major  portion  of  the  long,  slender  rostrum.  The 
anterior  end  is  but  slightly  decurved,  and  there  is  a  very  shallow  constriction  just 
posterior  to  it. 

The  lower  surface  of  the  skull  (plate  11,  fig.  c). — The  bones  of  the  palatal  surface 
have  been  largely  preserved,  but  have  been  badly  broken,  slightly  displaced  to  the  left 
side,  and  crushed  against  the  lower  surface  of  the  bones  of  the  roof  of  the  skull. 

The  basioccipital. — The  condyle  is  nearly  hemispherical  and  has  a  rather  long  neck, 
with  the  sides  flattened.  Low  ridges  appear  near  the  posterior  end  of  the  lower  face 
and  rise  rapidly  forward  until  just  anterior  to  the  suture  between  the  basioccipital  and 
the  basisphenoid  they  form  high  processes  on  the  sides  of  a  deep  notch. 

The  basisphenoiil  is  separated  from  the  basioccipital  by  a  distinct  suture.  On 
either  side  of  the  notch  described  above  there  are  prominent  processes,  the  tubera  basioc- 
ci/tilalia,  rounded  externally  and  with  flat,  oval  faces  looking  posteriorly.  These  pro- 
cesses contract  anteriorly,  disappearing  just  posterior  to  the  origin  of  the  basipterygoid 
processes.  The  lower  face  of  the  bone  is  flat  and  there  is  no  deep  pit;  the  bone  is  broken 


52  NEW   REPTILES   AND    STEGOCEPHALIANS    FROM 

in  this  place  and  is  filled  with  matrix,  but  an  examination  of  the  depression  shows  that 
the  edges  of  the  pieces  are  sharply  fractured  and  that  there  is  no  surface  leading  down 
into  a  pit.  The  basipterygoid  processes  are  prominent,  extend  slightly  forward  as  well 
as  outward,  and  terminate  in  slightly  convex  faces.  The  parasphenoid  process  is  of 
remarkable  length,  extending  forward  for  75  millimeters.  It  gradually  contracts  ante- 
riorly to  a  very  thin  lower  edge.  The  sides  of  the  process  are  flat,  about  20  millimeters 
high  at  the  posterior  end,  and  contract  to  not  over  5  millimeters  at  the  anterior  end. 
There  is  no  indication  of  a  division  into  upper  (presphenoid)  and  lower  (parasphenoid) 
portions. 

The  opisthotics  are  indistinguishable  from  the  exoccipitals;  they  extend  outward 
and  backward.  The  proximal  portion  of  the  complex  is  thick,  but  the  distal  portion 
contracts  to  a  thin  oval,  with  the  major  axis  placed  vertically.  To  the  outer,  i.  e., 
toward  the  quadrate,  side  of  the  extremity  of  the  right  opisthotic  there  is  attached  a 
small  fragment  of  bone  of  irregular  form.  This  was  at  first  regarded  as  a  displaced 
fragment  of  no  significance,  but  the  extremity  of  the  opisthotic  of  the  opposite  side  shows 
a  sutural  surface  in  the  same  position.  The  fragment  is  in  exactly  the  position  where 
McGregor  found  a  small  element  in  Mystriosuchus1  which  he  considered  to  be  calcified 
cartilage  and  identified  as  a  hyoid  element. 

The  stapes. — On  the  lower  side  of  the  right  opisthotic  there  is  preserved  a  portion 
of  a  very  slender  stapes  apparently  in  position.  The  portion  preserved  is  about  1.5 
centimeters  in  length,  with  a  diameter  of  less  than  1  millimeter.  The  outer  extremity 
is  lost,  but  the  inner  end  is  evidently  in  place  in  the  fenestra  ovalis;  the  crushed  condition 
of  the  specimen  in  this  region  renders  it  impossible  to  determine  the  exact  relations  of 
the  inner  end. 

The  quadratojugal  and  the  jugal  are  represented  on  the  lower  surface  by  their  thin 
lower  edges  only. 

The  pterygoids. — These  bones  are  badly  broken,  but  the  parts  are  sufficiently  well 
preserved  on  the  right  side  to  permit  a  restoration  of  a  major  portion  of  the  bones.  The 
articulation  with  the  basipterygoid  process  of  the  basisphenoid  is  accomplished  by  a 
well-formed,  slightly  concave  facet  on  the  inner  edge  of  the  bone,  which  is  slightly 
thickened  at  this  point.  The  quadrate  process  extends  backward,  with  a  narrow, 
concave  face  presented  downward,  which  rapidly  contracts  toward  its  distal  end. 
As  this  face  contracts,  the  body  of  the  process  assumes  a  vertical  position.  Union  with 
the  quadrate  is  accomplished  by  a  definite  suture  with  the  slender  pterygoid  process, 
which  is  of  considerable  vertical  extent.  The  external  process  of  the  pterygoid  extends 
outward  almost  at  a  right  angle  from  a  point  a  little  in  advance  of  the  basisphenoid 
process.  The  external  process  is  not  greatly  thickened,  but  the  posterior  end  descends 
somewhat  abruptly  from  the  palatal  surface,  and  from  this  point  the  bone  slants  gently 
forward  and  upward.  The  posterior  edge  is  thin  and  the  outer  corner  is  nearly  a  right 
angle;  the  outer  border  descends  rather  sharply  beneath  the  transverse.  The  anterior 
process  is  broad  posteriorly  and  contracts  anteriorly  as  its  inner  edge  is  cut  out  by  the 
development  of  the  interpterygoid  vacuity.  This  portion  of  the  bone  is  very  thin  and 
much  has  been  crushed  and  lost;  the  outline  of  the  interpterygoid  vacuity  as  represented 
is  uncertain,  but  enough  can  be  made  out  to  show  that  it  was  elongate,  broader  posteriorly, 
and  gradually  contracting  in  front  until  the  bones  of  the  two  sides  met  near  the  anterior 
end  of  the  parasphenoid  process.  The  suture  with  the  palatine  is  obscured,  as  the  latter 
bones  are  somewhat  overthrust  on  both  sides. 

The  transverse  is  thin  throughout ;  its  posterior  end  is  expanded  and  fits  closely  over 
the  lower  face  of  the  outer  part  of  the  external  process  of  the  pterygoid;  the  inner  edge  is 

1  McGregor,  J.  H.,  Memoirs  American  Museum  Natural  History,  vol.  ix,  pt.  11,  1906,  pi.  VH. 


THK    ri'I'KU    TRIASSIC    OK    WKSTKKX    TKXAS.  53 

marked  by  a  slight  ridge,  and  below  this  is  a  groove  which  is  continuous  with  a  foramen 
which  excavates  the  pterygoid  and  connects  with  the  small  palatine  vacuity  which  is 
not  visible  from  below.  The  bone  is  narrowed  in  the  median  portion  and  then  expands 
to  articulate  with  the  maxillary,  the  palatine,  and  the  jugal.  The  outer  face  is  bent 
sharply  down  and  forms  a  nearly  vertical  face;  its  distal  end  is  reflected  upon  the  inner 
sides  of  the  maxillary  and  jugal. 

The  palatines  are  elongate  bones  lying  between  the  maxillaries  and  the  pterygoid. 
On  the  right  side  the  palatine  is  separated  by  a  fracture  from  the  maxillary,  but  on  the 
left  side  the  bones  are  in  contact.  The  surface  of  the  palatine  is  convex  downwardly 
in  the  middle  of  its  length,  but  the  anterior  and  posterior  ends  are  flatter.  The  greatest 
height  of  the  convexity  is  near  the  inner  edge  of  the  bone  and  the  whole  surface  of  the 
middle  portion  is  slightly  rugose. 

The  anterior  termination  of  the  pterygoids  and  the  palatines  is  uncertain.  They 
apparently  join  the  vomers  near  the  median  line,  but  as  the  premaxillaries  of  the  two 
sides  meet  in  the  median  line  as  far  back  as  a  point  just  below  the  posterior  edge  of 
the  external  narial  opening,  the  palatines,  pterygoids,  and  vomers  must  have  risen 
somewhat  in  the  skull  at  this  point.  Just  posterior  to  the  point  where  the  premaxillaries 
terminate,  the  inner  edges  of  the  median  bones  of  the  palate  are  slightly  excavated  and 
rounded,  indicating  the  position  of  the  very  narrow  internal  nares,  but  whether  the 
boundaries  of  these  openings  are  formed  by  the  vomers  alone  or  by  the  vomers  and 
pterygoids  can  not  be  made  out.  There  is  no  suggestion  of  a  median  septum,  but  the 
opening  was  probably  paired.  In  the  light  cast  by  the  study  of  the  skull  of  Leptosuchus, 
this  interpretation  may  be  erroneous. 

The  maxillaries  appear  on  the  lower  side  of  the  skull  only  as  the  alveolar  edges; 
anterior  to  the  external  narial  opening  they  join  the  premaxillaries  by  oblique  sutures 
running  backward  and  inward,  so  that  the  posterior  ends  of  the  premaxillaries  extend 
backward  as  long  processes  between  the  maxillaries. 

The  premaxillaries  extend  forward  with  nearly  straight  outer  sides;  the  lower 
surface  is  divided  between  the  alveolar  edges  and  smooth  convex  surfaces;  the  two  bones 
meet  in  a  broad  median  symphysis.  This  symphysis  is  divided  into  an  upper  and  a  lower 
part;  between  the  two  articulating  surfaces  there  is  a  smooth,  somewhat  concave  area, 
indicating  the  presence  of  a  narrow  median  cavity  running  nearly  the  full  length  of  the 
rostrum.  On  either  side  of  this  groove  the  palatal  surface  of  the  premaxillaries  is  raised 
into  convex  (longitudinally)  ridges,  forming,  with  similar  process  on  the  dentaries,  a 
buttress  which  prevented  injury  to  the  teeth  when  the  jaws  were  snapped  together. 

The  teeth  are  typically  phytosaurian  in  shape  and  arrangement.  The  posterior 
teeth  are  broader  and  lower,  with  sharp  anterior  and  posterior  serrate  cutting  edges. 
The  inner  side  of  each  tooth  is  nearly  flat,  except  at  the  tip,  where  the  convexity  becomes 
greater;  the  outer  side  is  decidedly  convex.  The  cutting  edges  are  sharply  crenulate 
from  the  apex  nearly  to  the  base.  The  greater  part  of  the  teeth  are  lost,  but  certainly 
at  the  middle  of  the  premaxillaries  the  teeth  were  elongate  and  slender.  The  inner  side 
of  the  few  anterior  ones  preserved  is  less  convex  than  the  outer  and  the  cutting  edges 
are  lower;  the  crenulations  do  not  appear  on  the  single  tooth,  which  is  well  preserved, 
but  t  hey  were  probably  present  to  some  extent.  The  extremity  of  the  snout  was  occupied 
by  four  large  teeth,  which  on  the  right  side  are  represented  only  by  the  base  of  the  inner 
one  and  the  apex  of  the  just  erupting  outer  one.  The  apex  of  the  outer  tooth  shows 
the  same  disparity  between  the  convexity  of  the  inner  and  outer  sides  that  appears  in 
the  other  teeth  of  the  scries.  There  are  47  teeth  and  alveoli  on  each  side  in  the  upper 
jaws.  The  separation  of  the  two  sides  of  the  skull  at  and  anterior  to  the  external  narial 
opening  permits  of  some  observations  upon  this  region.  As  shown  in  figure  21,  there 
is  a  pair  of  bones,  at  the  level  of  the  surface  of  the  skull  posterior  to  the  narial  opening, 


54 


NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 


nai 


FIG.  21. — Promystrio- 
suchus  ehlersi. 

Median    surface    of    the 
narial  region,  left  side. 
na.,  nasal.      X  0.6. 


which  divides  the  nares  some  distance  below  the  level  of  the  rim.  These  bones  are  thin, 
but  nearly  a  centimeter  in  height  on  the  broad  inner  surface,  which  was  closely  applied 
to  the  bone  of  the  opposite  side.  These  are  probably  extensions  of  the  nasals.  On 
the  left  side,  in  what  is  apparently  a  direct  continuum  with  the  median  palatal  element, 
probably  the  palatine  (vomer  ?),  there  is  a  slender  bar  of  bone  distinct  from  both  the 
nasal  and  the  premaxillary.  As  this  bar  is  above  the  premaxillaries  in  the  region  where 
they  meet  in  the  median  line,  it  can  not  be  a  bar  separating  the  internal  nares;  rather  it 
seems  to  be  a  bar  vertically  placed  beneath  the  nasals  and  denning  an  opening  which 
permits  the  nasal  to  open  laterally  into  passages  which  lead  back  to  the  somewhat 
posteriorly  placed  internal  nares.  The  separate  character  and 
distinct  identity  of  this  bar  is  proven  by  the  fact  that  it  was 
surrounded  by  matrix,  which  has  penetrated  between  it  and  the 
adjacent  bones,  and  by  its  rounded  edges  revealed  under  the 
binocular  microscope. 

The  posterior  face  of  the  skull  (plate  11,  fig.  D). — The  crushing 
of  the  skull  has  almost  completely  closed  the  foramen  magnum,  and 
in  the  restoration  allowance  has  been  made  for  this  depression  as 
accurately  as  possible.  The  sutures  between  the  elements  forming 
the  edges  of  the  foramen  magnum  can  not  be  made  out. 

The  basioccipital  carries  a  good-sized,  nearly  hemispherical 
condyle;  the  sides  of  the  neck  run  forward  and  upward  to  join 
the  exoccipital-opisthotics.  It  has  been  impossible  to  determine 
the  position  of  any  of  the  nerve  outlets. 

The  exoccipital  and  the  opisthotic  are  closely  fused;  the  opis- 
thotic  portion  extends  outward  and  backward  at  a  fairly  sharp  angle;  the  outer  portion 
becomes  thinned  laterally,  but  retains  its  vertical  extent;  the  outer  end  terminates  freely 
below  the  distal  end  of  the  squamosal. 

The  supraoccipital  is  a  rather  broad  plate  inclined  sharply  forward  in  the  median 
line,  but  becoming  more  nearly  vertical  towrard  the  sides;  it  is  closely  attached  to  the 
slender  parietals  above,  which  are  visible  only  as  thin  edges  from  the  rear.  The  post- 
temporal  openings  are  entirely  closed,  if  they  were  present,  which  is  quite  probable. 
An  enlargement  visible  on  the  upper  edge  of  the  opisthotic  in  the  usual  position  of  the 
openings  may  be  due  to  crushing.  Small  post-temporal  openings  have  been  shown  in 
the  restoration. 

The  squamosal  has  a  relatively  small  presentation  on  the  posterior  face  of  the  skull ; 
it  sends  a  short  prong  inward  between  the  distal  end  of  the  opisthotic  and  the  supraoc- 
cipital and  a  second  one  above  the  supraoccipital  to  unite  with  the  parietal.  Just  above 
the  distal  end  of  the  opisthotic  is  the  prominent  posterior  termination  of  the  squamosal, 
and  below  this  is  the  small  fragment  of  bone  on  the  outer  side  of  the  opisthotic  which 
McGregor  identified  as  a  hyoid  element  in  Mystriosuchus.  Externally  the  squamosal 
sends  a  strong  process  forward  and  outward  to  join  the  quadratojugal;  the  lower  surface 
is  excavated  for  the  reception  of  the  upper  end  of  the  quadrate. 

The  quadrate  has  a  nearly  quadrangular  posterior  surface.  This  surface  inclines 
inward  and  forward  beneath  the  opisthotic;  the  upper  half  of  the  inner  edge  forms  the 
articulation  for  the  pterygoid.  The  outer  edge  is  covered  by  the  quadratojugal,  which 
sends  a  short  process  around  the  outer  edge  on  to  the  posterior  face  near  the  outer  lower 
corner.  About  midway  up  the  outer  edge  there  is  a  good-sized  quadrate  foramen 
surrounded  by  the  quadrate  and  quadratojugal.  There  is  no  indication  that  the  quadrate 
process  of  the  pterygoid  appeared  on  the  outer  face  of  the  skull,  as  described  by  Huene1 
in  Mystriosuchus  pleiningeri. 

1  Huene,  F.  v.,  Geolog.  u.  Paleontolog.  Abhdlg.,  N.  F.,  Bd.  x,  Hft.  1,  s.  81,  1911. 


THE   UPPER   TRIASSIC   OF   WESTERN   TEXAS.  55 

A  review  of  the  known  skulls  of  the  Parasuchia  reveals  the  fact  that  they  may  be 
divided  into  two  more  or  less  clearly  marked  groups — those  with  long,  slender,  depressed 
rostra  and  those  with  elevated  rostra.  To  the  first  group,  the  Mystriosuchid  group, 
belong  Myslriosuchus,  Rhytidiodon,  Palcorhinus,  and  Promystriosuchus;  to  the  second 
group  belongs  Phytosaurus  (Belodon).  Intermediate  between  the  two  are  the  forms 
which  have  been  described  by  Cope  as  Belodon  buceros  and  by  Mehl  as  Machawoprosopus 
validus.  In  the  opinion  of  some  workers,  Belodon  buceros  Cope  and  Machceroprosopus 
ml/dm  Mehl  should  be  placed  in  the  genus  Phytosaurus.  The  two  specimens  described 
in  this  volume  as  Leptosuchus  help  to  further  bridge  over  the  gap  between  the  two  groups. 

The  form  described  as  Promystriosuchus  belongs  in  the  Mystriosuchid  group  and 
is  nearest  to  Angistorhinus.  Because  of  its  retention  of  certain  primitive  characters, 
it  will  be  best  to  compare  it  first  with  Mesorhinus,  the  earliest  and  most  primitive  of  the 
Parasuchia.  Mesorhinus  was  described  by  Jaekel1  from  the  middle  Bunter  sandstone 
of  Bernburg. 

COMPARISON  WITH  MESORHINUS. 

The  anterior  portion  of  the  rostrum  of  the  specimen  was  not  recovered,  and 
Huene  considers  that  it  has  been  made  too  long  in  the  restoration  by  Jaekel.  Granting 
the  correctness  of  Jacket's  restoration,  which  would  be  the  maximum  possible  length 
of  the  rostrum,  there  is  still  a  great-disparity  between  the  relative  lengths  of  the  prenarial 
and  postnarial  portions  of  the  skull  and  the  same  measurements  in  Mystriosuchids 
from  the  Upper  Triassic.  Measuring  from  the  anterior  end  of  the  narial  opening,  Jacket's 
figure  (as  copied  by  Huene)  gives  a  relative  proportion  of  lengths  between  the  prenarial 
and  postnarial  portions  of  the  skull  as  5  :  6;  the  same  measurements  on  the  figure  given 
by  Abel  (Stamme  der  Wirbelthiere,  p.  516)  give  proportions  of  4  :  5.  In  Promystriosuchus 
the  rostrum  has  become  relatively  much  elongated,  a  distinctive  character  of  the  special- 
ized Parasuchians  of  the  Upper  Triassic,  the  proportional  lengths  being  as  3  :  2.  In 
Mesorhinus  the  narial  opening  is  elongate  and  clearly  divided  by  a  septum  at  the  level 
of  the  surface  of  the  skull,  formed  by  an  anterior  extension  of  the  nasals;  the  antorbital 
vacuity  reaches  either  to  the  middle  of  the  narial  opening  or  only  a  little  way  anterior 
to  the  posterior  edge,  according  to  figures  of  the  lateral  and  the  upper  view  of  the  skull 
as  given  by  Jaekel  (copied  by  Huene);  the  lateral  temporal  opening  is  nearly  circular; 
the  parieto-squamosal  bar  defining  the  inner  border  of  the  supratemporal  foramen  is 
complete  and  at  the  level  of  the  roof  of  the  skull;  the  supratemporal  foramen  itself  is 
entirely  on  the  top  of  the  skull;  the  squamosals  do  not  extend  far  posterior  to  the  occip- 
ital condyle.  In  Promystriosuchus  the  narial  opening  is  round,  is  surrounded  by  a  high 
rim,  and  the  septum  is  far  down  within  the  cavity  of  the  nares;  the  antorbital  opening  is 
elongate  and  reaches  as  far  forward  as  the  middle  of  the  narial  opening;  the  lateral  tem- 
poral opening  has  assumed,  more  or  less  perfectly,  the  characteristic  parallelogrammic 
form  of  the  Parasuchia;  the  parieto-squamosal  bar  is  at  the  level  of  the  roof  of  the  skull, 
and  the  supratemporal  opening  is  entirely  upon  the  upper  surface;  the  squamosals  do 
not  extend  far  posterior  to  the  occipital  condyle. 

On  the  posterior  surface  of  the  skull  the  shortness  of  the  opisthotic  process  in 
Mesorhinus  is  a  striking  difference  from  the  condition  found  in  the  younger  Parasuchia. 

On  the  lower  surface  the  palate  of  Mesorhinus,  as  figured  by  Jaekel,  is  radically 
different  from  that  of  the  majority  of  the  Parasuchia.  The  pterygoids  lack  the  strong 
external  process;  the  transverse  articulates  with  the  outer  edge  of  the  pterygoid  instead 
of  underlying  an  external  process;  the  palatine  vacuity  is  large,  lying  between  the  pala- 
tines, pterygoids,  maxillaries,  and  transverse.  The  peculiar  articulation  between  the 

1  Jaekel.  ()..  Sitz.  Her.  d.  Gesell.  Naturf.  Fmmde,  Berlin,  No.  5,  p.  197,  1910;  see  also  Huene,  F.  v.,  Geol.  u. 
Paleont.  Ahhdlg.,  X.  F.,  Bd.  x,  Hft.  1,  s.  50,  1911. 


56 


NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 


pterygoid  and  the  palatines  is  not  found  in  any  other  form  of  the  Parasuchia.  In 
Prornystriosuchus  there  is  a  strong  external  process  of  the  pterygoids  which  is  underlain 
by  the  posterior  end  of  the  transverse;  the  palatine  vacuity  is  represented  by  a  small 
foramen  between  the  palatine  and  the  transverse,  which  appears  on  the  lower  surface 
near  the  posterior  end  of  the  transverse. 

The  primitive  characters  of  Prornystriosuchus  appear  in  the  elevated  parieto-squamo- 
sal  arch,  the  relatively  anterior  position  of  the  narial  opening,1  and  the  elongation  of  the 
parasphenoid  process.  The  other  characters  cited  are  those  of  the  more  specialized 
Parasuchia,  and  it  is  evident  that  the  form  here  described  must  be  placed  in  the  Mystrio- 
suchid  group  of  the  Phytosauridae.  The  primitive  characters  are  conservative  features 
which  are  found  in  at  least  one  other  member  of  the  same  group  and  family. 

COMPARISON  WITH  ANGISTORHINUS. 

Angistorhinus-  is  in  many  ways  the  nearest  known  form  to  Prornystriosuchus. 
A  consideration  of  the  comparative  characters  will  make  more  evident  the  similarities 


F  10.  22. — Angislorhinus,  lateral  view  of  skull,  after  Mehl. 

A.  Lateral  view  of  .skull. 

B.  Upper  view  of  skull. 

C.  Lower  view  of  skull. 

D.  Posterior  view  of  skull,  somewhat  larger. 
smx.,  septomaxillary.     Other  lettering  as  usual. 

and  differences  between  Promystriosuchus  and  the  other  Mystriosuchids.  The  relative 
proportions  in  length  of  the  prenarial  and  postnarial  portions  of  the  skull  of  Angistorhinus 
are  as  10  :  6.4,  or  approximately  5  :  3;  the  antorbital  vacuity  is  elongate  and  extends  as 
far  forward  as  the  anterior  edge  of  the  narial  opening ;  the  opening  is  surrounded  by  a 

1  Huene,  in  the  Geol.  u.  Palcont.  Abhdlg.,  N.  !•'.,  Bd.  x,  lift.  1,  s.  5:i,  has  suggested  that  the  position  of  the 
narial  opening  and  the  elongation  of  the  rostrum  are  hvo  distinct  things  and  that  the  retreat  of  the  nares  is  connected 
with  the  shortening  of  the  posterior  part  of  the  skull.     The  relation  between  the  antorbital  vacuity  and  the  naivs  is 
regarded  by  him   as  a  phylogenetic  character;  as  the  nares  retreated  the  antorbital  opening  would  appear  more  and 
more  anteriorly  in  the  skull. 

2  Mehl,  M.  G.,  Journal  of  Geology,  vol.  21,  No.  2,  p.  186,  1913;  Ibid.,  vol.  23,  No.  2,  p.  129,  1915. 


.   THE   UPPER   TRIASSIC   OF   WESTERN   TEXAS.  57 

high  rim,  but  the  septum  is  placed  deeply  within  the  cavity;  the  parieto-squamosal  arch 
is  complete  and  on  a  level  with  the  roof  of  the  skull;  the  interpterygoid  vacuity  is 
relatively  large,  and  the  parasphenoid  process  is  long,  reaching  to  the  anterior  end  of  the 
vacuity.  The  two  forms  differ  in  that  in  Angistorhinus  the  squamosals  are  much  larger 
and  extend  well  beyond  the  occipital  condyle,  so  that  it  is  not  visible  from  above;  there 
is  a  much  sharper  depression  of  the  rostrum  anterior  to  the  external  nares;  the  anterior 
end  of  the  rostrum  is  much  more  down-turned  and  is  wider;  the  pterygoid  is  represented 
by  Mehl  as  having  no  external  process  and  the  transverse  joins  it  laterally,  not  by 
underlying  an  external  process;  the  posterior  arm  of  the  parietal  is  short,  the  greater  part 
of  the  upper  edge  of  the  posterior  part  of  the  skull  being  formed  by  the  squamosal;  the 
opisthotic  process  extends  out  to  the  squamosal,  but  is  surrounded  by  it  both  above  and 
externally;  the  post-temporal  foramen  is  relatively  large. 

COMPARISON  WITH   PALEOBHINUS.' 

If  Huene's  suggestion  of  the  phylogentic  value  of  the  relative  position  of  the  externa 
nares  and  the  antorbital  vacuity  is  correct,  Paleorhinus  retains  the  primitive  character 
in  a  marked  degree,  for  the  antorbital  vacuity  is  entirely  posterior  to  the  nares  and  has  a 
rounded  anterior  outline,  indicating  a  very  different  form  of  the  jaw-muscle;  the  squa- 
mosal has  a  very  large  extension  behind  the  occipital  condyle.  The  proportion  between 
the  relative  lengths  of  the  prenarial  and  postnarial  portions  of  the  skull  is  as  8  : 8.8, 
or  nearly  as  1  :  1,  approaching  in  this  the  probable  condition  in  Mesorhinus.  On  the 
other  hand,  the  specialized  character  of  the  skull  appears  in  the  depression  of  the 
parieto-squamosal  arch,  the  shortness  of  the  posterior  bar  of  the  parietal,  the  elevated 
rim  of  the  external  nares,  the  position  of  the  internal  nares  posterior  to  the  external, 
the  small  interpterygoid  vacuity  and  the  short  parasphenoid,  the  strong  external  process 
of  the  pterygoid  with  the  transverse  articulating  with  its  lower  surface,  and  the  position 
of  the  palatine  vacuity  anterior  to  the  middle  of  the  transverse.  The  characters  de- 
scribed by  Lees2  of  the  elongate  vomers  reaching  back  to  take  part  in  the  anterior  edge 
of  the  interpterygoid  vacuity,  the  otic  foramen  between  the  squamosal  and  the  quad- 
ratojugal,  and  the  position  of  the  quadrate  foramen  on  the  lateral  surface  of  the  skull 
have  all  been  questioned  by  Mehl  and  Huene3  and  are  so  unlike  the  normal  characters 
of  the  other  Parasuchia  that  they  can  not  be  accepted  or  discussed  until  the  skull  is 
reexamined.  The  improbability  of  the  existence  of  an  otic  foramen  in  the  position  de- 
scribed by  Lees  is  further  emphasized  by  the  discovery  of  the  stapes  in  the  normal  position 
of  the  lower  side  of  the  opisthotic  in  Promysiriosuchus. 

COMPARISON  WITH  MYSTRIOSUCHUS. 

This  comparison  is  based  on  the  published  descriptions  of  Myslriosuchus  planirostris 
and  M.  pleiningeri  by  McGregor  and  Huene.4 

The  lengths  of  the  prenarial  and  postnarial  portions  of  the  skull  of  Mystriosuchus 
are  very  closely  as  5  :  2 ;  the  antorbital  openings  are  elongate  and  extend  forward  either 
to  the  anterior  end  of  the  nares  (planirostris)  or  slightly  anterior  to  them  (pleiningeri) ; 
the  nasal  septum  reaches  the  level  of  the  skull;  the  parietals  have  no  posterior  bar 
denning  the  inner  side  of  the  supratemporal  opening;  the  parietals  descend  to  the  top 

1  \\illiston,  S.  \V.,  Journal  of  Geology,  vol.  xn,  p.  696,  1904;  Lees,  J.  H.,  Journal  of  Geology,  vol.  xv,  N.I.  2. 

p.  121,  1907. 

!  Lees,  J.  H.,  The  Skull  of  I'nlmrhinus,  Journal  of  Geology,  vol.  xv,  No.  2,  p.  133,  1907. 
'Mehl,  M   G.,  Journal  of  Geology,  vol.  xxm,  No.  2,  p.  157,  1915;  Huene,  F.  v.,  Neues  Jahrb.  f.  Min.  Geol. 

u.  Pal.,  No.  19,  p.  587,  1909. 
1  McGregor,  J.  H.,  Memoirs  American  Museum  Natural  History,  vol.  ix,  pt.  II,  1906;  Huene,  F.  v.,  Geolog- 

ische  u.  Paleontologische  Abhandlungen,  N.  F.,  Bd.  x,  Hft.  1,  p.  68,  1911. 


58 


NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 


of  the  opisthotic  and  the  openings  look  as  much  backward  as  upward;  the  posterior  face 
of  the  skull  is  very  similar,  except  for  the  depressed  parieto-squamosal  bar;  the  post- 
temporal  opening  is  small,  and  the  opisthotics  extend  out  to  the  squamosal  and  are 


FIG.  23. 
Paleorhinus,  after  Lees.     Lettering  as  usual. 

A.  Lateral  view  of  skull.         B.  Upper  view  of  skull. 
Mystriosuchus,  after  McGregor. 

D.  Upper  view  of  skull.          E.  Lower  view  of  skull. 


C.  Lower  view  of  skull. 
F.  Lateral  view  of  skull. 


overlapped  by  it.  In  the  specimen  of  M .  planiroslris,  described  by  McGregor,  the  small 
element  on  the  outer  side  of  the  distal  end  of  the  opisthotic  is  apparently  calcified  car- 
tilage; in  Promyslriosuchus  the  fragment  in  this  position  is  true  bone;  the  opisthotic 
process  stands  a  little  higher  above  the  condyle  in  Promystriosuchus.  On  the  lower 


THE   UPPER   TRIASSIC    OF   WESTERN   TEXAS. 


59 


face  of  the  skull  the  relation  of  the  transverse  to  the  pterygoid  is  very  different  in  the 
two  forms.  In  M.  planirostris  and  pleiningeri  the  transverse  lies  external  to  the  process 
of  the  pterygoid  and  articulates  with  it  laterally  instead  of  underlying  it;  the  outer 
corner  of  the  dependent  process  is  formed  entirely  by  the  transverse;  the  palatine  foramen 
is  small,  but  lies  anterior  to  the  middle  of  the  transverse;  the  quadrate  process  of  the 
pterygoid  is  shorter  and  articulates  with  an  elongate  process  of  the  quadrate;  the  suture, 
as  figured  by  McGregor,  lies,  at  least  on  the  lower  face,  near  to  the  basisphenoid  process  of 
the  pterygoid;  there  is  but  a  small  interpterygoid  space  and  the  parasphenoid  process  is 
short  or  in  large  part  covered  by  the  pterygoids;  the  internal  nares  are  directly  beneath 
the  external  nares;  the  inner  edges  of  the  palatines  are  elevated,  but  do  not  show  the 
rugosity  which  appears  on  these  bones  in  Promystriosuchus.  It  is  apparently  this  ele- 
vated edge  of  the  palatines  which  Huene1  refers  to  as  the  median  edge  of  the  pterygoids. 


B 


Fio.  24. — Phyto&awus  (Machceroprosopus) ,  after  Mehl. 

A.  Lateral  view  of  skull. 

B.  Upper  view  of  skull. 

C.  Posterior  view  of  skull. 

D.  Posterior  view  of  skull  of  Mystriosvchus,  after  McGregor. 

E.  Posterior  view  of  skull  of  Phytosaurus  kappfi. 
Lettering  as  usual. 

COMPARISON  WITH  RnYTinioDON.2 

• 

Most  of  the  material  representing  this  genus  was  recovered  from  the  Triassic 
coal-beds  of  Egypt,  Chatham  County,  North  Carolina.  Most  of  the  skulls,  as  reported 
by  McGregor,  are  in  a  very  fragmentary  condition;  a  single  skull,  lacking  the  anterior 
end,  permits  of  some  comparison.  The  antorbital  opening  extends  beyond  the  anterior 
edge  of  the  external  nares;  the  orbits  have  a  considerable  lateral  presentation;  the 
parieto-squamosal  bar  is  depressed;  the  squamosal  region  extends  well  posterior  to  the 
occipital  condyle;  the  palatine  vacuities  are  at  the  extreme  anterior  end  of  the  transverse. 

1  Huene,  F.  v.,  loc.  cit.,  p.  17.        *  McGregor,  J.  H.,  loc.  cit.,  p.  58. 


60  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

The  figures  show  this  specimen  as  having  no  interpterygoid  vacuity  and  no  parasphenoid ; 
this  is,  in  all  probability,  the  result  of  the  condition  of  the  specimen.  There  is  an  elevated 
rim  to  the  external  nares,  and  the  septum  is  at  the  level  of  the  top  of  the  skull.  By 
utilizing  a  specimen  in  the  New  York  State  Museum,  which  he  assumes  to  have  been  of 
the  same  size  as  the  one  in  the  American  Museum,  McGregor  determined  the  prenarial 
and  postnarial  proportion  to  be  as  3  :  2. 

COMPARISON  WITH  PHYTOSAURUS  (MACH^ROPHOSOPUS). 

The  specimen  described  as  Machaeroprosopus  by  Mehl1  and  regarded  by  him  as 
congeneric  with  Belodon  buceros  Cope  is  in  many  ways  intermediate  between  the  Mystrio- 
suchid  and  the  Phytosaurid  groups  of  the  Parasuchia.  The  elevation  of  the  posterior 
half  of  the  rostrum,  the  posterior  position  of  the  nares,  and  the  extreme  depression  of 
the  parieto-squamosal  arch  are  all  characters  of  the  Phytosaurid  group,  while  the  long, 
slender  anterior  half  of  the  rostrum  is  distinctly  Mystriosuchid-like.  The  prenarial 
portion  of  the  rostrum  is  relatively  short,  its  proportional  length  to  the  postnarial  portion 
being  as  7.8  :  8.3,  or  a  little  less  than  1:1;  the  antorbital  opening  is  elongate  and  reaches 
almost  to  the  anterior  end  of  the  extern!  nares;  the  parietals  have  no  posterior  bar,  and 
the  squamosal  region  is  much  extended,  reaching  far  behind  the  condyle;  the  supratem- 
poral  openings  look  almost  entirely  to  the  rear;  Mehl2  has  drawn  in  outline  a  rather 
broad  bar  separating  the  supratemporal  from  the  post-temporal  openings  on  the  posterior 
surface  of  the  skull.  This  is  probably  correct,  as  its  width  is  indicated  by  the  broken 
edges,  but,  if  so,  it  leaves  a  much  larger  post-temporal  opening  than  occurs  in  any  other 
of  the  Phytosaurid  group. 

1  Mehl,  M.  G.,  Quarterly  Bulletin  University  of  Oklahoma,  n.  s.,  No.  103,  1916. 

2  Mehl,  M.  G.,  loc.  cit.,fig.  3. 


THE    UPPER   TRIASSIC   OF   WESTERN   TEXAS.  61 

NEW  PARASUCHIANS,  LEPTOSUCHUS  CROSBIENSIS  AND  LEPTO- 
SUCHUS  IMPERFECTA,  FROM  CROSBY  COUNTY,  TEXAS. 

The  first  skull  (Leptosuchus  crosbiensis,  No.  7522,  University  of  Michigan)  is 
singularly  perfect.  All  of  the  bones  except  those  of  the  posterior  portion  of  the  upper 
suiface  are  preserved  in  place  and  the  loose  ones  were  found  close  to  the  specimen. 
One  half  of  the  lower  jaw  was  found  overlying  the  skull,  and  the  posterior  portion  of  the 
other  half  was  found  not  far  distant.  Total  length  of  the  skull,  87.5  cm. 

The  second  skull  (No.  7523,  University  of  Michigan)  is  much  larger  than  the 
first  and  was  found  entirely  washed  out  and  lying  on  the  surface  as  a  mass  of  fragments. 
Some  parts  had  disappeared  and  the  skull  as  mounted  is  in  part  restored.  Total  length 
as  restored  112  cm. 

Skull  No.  7522  is  so  singularly  perfect  that  it  warrants  a  rather  full  description. 
It  was  completely  covered  when  found,  the  removal  of  the  half  of  the  lower  jaw  over- 
lying it  leading  to  its  discovery.  The  matrix  is  a  fine  yellowish  clay  broken  into 
innumerable  small  pieces,  between  which  are  sheets  of  calcite  not  over  0.1  mm.  thick. 
Ihe  skull  is  slightly  compressed,  the  right  side  is  a  little  displaced  upward,  and  the  bones 
of  the  posterior  portion  are  a  little  distorted.  The  extremely  complex  fracturing  of  the 
matrix  compelled  a  fracturing  of  the  bone  which  is  only  slightly  less  in  degree,  but  the 
fragments  are  all  in  position.  The  skull  was  collected  in  a  block  of  matrix  and  has  been 
prepared  and  mounted  by  the  painstaking  and  skilful  work  of  Mr.  William  H.  Buettner. 

Particularly  important  is  the  preservation,  in  the  natural  position,  of  the  extremely 
thin  bones  of  the  palatal  region.  This  permits  a  determination  of  the  complete  osteology 
of  the  skull. 

The  upper  surface  of  the  skull. — The  best  idea  of  the  position  and  relation  of  the 
bones  may  be  gained  from  figure  25  A.  The  narrow  upper  surface  of  the  squamosals  is  in 
striking  contrast  with  most  other  forms  of  the  Phytosaurs. 

The  lateral  surface  of  the  skull. — Seen  from  the  side,  the  premaxillaries  are  similar 
in  form  and  relations  to  the  same  bones  in  the  majority  of  the  forms  of  the  Mystriosuchid 
group.  The  anterior  end  is  sharply  down-curved,  with  a  decided  notch  behind  the 
prominent  anterior  tusks  for  the  reception  of  the  tusks  of  the  lower  jaw.  Near  the 
middle  of  the  bone  there  is  a  low  but  very  evident  prominence  on  the  upper  surface. 
This  seems  to  be  a  common  and  normal  structure  in  most,  if  not  all,  of  the  Mystriosuchid?. 
It  occurs  in  all  the  specimens  preserved  in  the  University  of  Michigan  collection  and  is 
figured  and  described  by  v.  Huene  in  M .  pleiningeri.  Huene  attributed  the  prominence 
to  an  accident,  but  it  is  clear  that  it  may  be  a  normal  feature.  The  peculiar  condition 
found  in  this  region  in  specimen  No.  7523,  University  of  Michigan,  is  described  below, 
but  is  not  yet  understood. 

The  articulation  with  the  maxillary  starts  on  the  alveolar  edge,  just  posterior  to 
the  twenty-third  tooth.  The  surface  of  the  premaxillary  is  devoid  of  rough  sculpture, 
unless  it  be  at  the  extreme  posterior  end,  where  it  approaches  the  nasal  prominence  just 
anterior  to  the  external  nares. 

The  maxillary  has  the  usual  position  and  relationships.  It  forms  the  lower  border 
and  the  anterior  border  of  the  antorbital  vacuity  and  the  anterior  part  of  the  upper 
border  of  the  same  opening.  The  portion  below  the  vacuity  is  smooth  and  the  alveolar 
edge  is  convex  downward.  There  are  21  tooth-sockets  in  the  maxillary,  which  are 
rounded  in  the  anterior  portion,  but  by  the  eighth  or  tenth  from  the  anterior  end  become 
decidedly  oval  in  outline.  The  upper  portion  of  the  maxillary  is  more  rugose.  The 
position  of  the  suture  between  it  and  the  nasals  is  indicated  by  the  sudden  increase  in 
the  coarseness  of  the  rugositio,  as  well  as  the  change  in  the  course  of  the  bone-fibers. 


62 


NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 


The  exact  outline  of  the  nasals  is  not  determinable.  The  anterior  end  appears  to 
be  opposite  a  point  halfway  between  the  anterior  end  of  the  maxillaries  and  the  anterior 
end  of  the  antorbital  vacuity.  The  bone  is  marked  by  a  deep  radiating  sculpture  which 
apparently  starts  from  the  region  around  the  external  nares,  but  is  more  pronounced 
on  the  sides  of  the  bone.  The  eminence  of  the  nose  is  2  or  3  centimeters  anterior  to  the 


FIG.  25. — Leptosuchus  crosbiensis,  No.  7522,  U.  of  Mich.      X  0.16. 
A.  Lateral  view  of  skull.         B.  Upper  view  of  skull.         C.  Lower  view  of  skull. 

Lettering  as  usual. 

external  nares,  and  from  this  point  the  front  slopes  gently  down  to  join  the  premaxillaries. 
The  lower  edge  of  the  nasals  is  excluded  from  the  upper  edge  of  the  antorbital  vacuity 
by  the  juncture  of  the  maxillary  and  the  lachrymal. 

It  is  impossible  to  determine  the  exact  outline  of  the  septornaxillaries.  It  is  evident 
from  the  direction  of  the  bone-fibers  that  a  distinct  element  is  present  in  front  of  the 
nares,  perhaps  taking  part  in  their  anterior  edge,  but  the  sutures  have  not  been  made 
out  with  certainty. 

Thejugals  articulate  with  the  maxillaries  by  a  broad  sutural  surface  which  underlies 
the  posterior  end  of  the  maxillary.  A  broad  vertical  process  rises  to  articulate  with  the 
postorbital  and  a  relatively  slender  bar  extends  backward  to  articulate  with  the  quad- 
ratojugal  and  the  quadrate.  The  articulation  with  the  quadratojugal  is  as  described 
previously  by  the  author.1  The  quadratojugal  is  deeply  cleft  on  the  lower  edge  and 

1  Case,  E.  C.,  Journal  of  Geology,  vol.  xxvm,  p.  530-531,  1920. 


THE   UPPER   TRIASSIC   OF   WESTERN   TEXAS.  63 

the  jugal  is  deeply  dovetailed  into  it.  This  method  of  articulation  is  confirmed  by  its 
presence  in  two  specimens  in  the  University  of  Michigan  collection.  The  jugal  is  visible 
along  the  lower  edge  of  the  skull  to  the  posterior  end  of  the  quadrate. 

The  quadratojugal  is  a  nearly  triangular  plate  which  covers  the  outer  side  of  the 
quadrate  almost  entirely  and  takes  slight  part  in  the  formation  of  the  posterior  edge  of 
the  lateral  temporal  fenestra. 

The  quadrate  appears  on  the  side  of  the  skull  only  at  the  posterior  lower  corner  and 
as  a  thin  edge  at  the  posterior  line  of  the  skull. 

The  squamosal  has  a  very  large  lateral  presentation  and  a  correspondingly  small 
presentation  on  the  upper  surface,  apparently  less  than  in  any  previously  described  form. 
The  lateral  surface  is  nearly  vertical;  its  posterior  portion  extends  52  mm.  beyond  the 
end  of  the  opisthotic,  forming  a  very  decided  projection  at  the  posterior  end  of  the  skull. 
From  the  lower  edge  of  this  projecting  portion  there  is  a  strong  descending  process, 
the  anterior  edge  of  which  forms  the  posterior  border  of  the  otic  notch.  Within  the 
notch  the  upper  part  of  the  quadrate  and  a  portion  of  the  distal  end  of  the  opisthotic 
can  be  seen  from  the  side. 

The  posterior  face  of  the  skull. — This  face  of  the  skull  is  more  distorted  than  any 
other,  due  to  the  upward  movement  of  the  right  side  in  the  compression  accompanying 
fossilization.  The  occipital  condyle  is  forced  somewhat  to  the  left  and  the  bones  above 
the  condyle  are  somewhat  broken  and  displaced.  It  is,  however,  easy  to  restore  the 
original  condition. 

The  parietals  descend  very  abruptly  and  lie  upon  the  upper  edge  of  the  opisthotic. 
The  post-temporal  opening  was  either  entirely  occluded  or  was  represented  by  a  small 
opening  not  greater  than  a  large  foramen.  The  outer  edge  of  the  parietal  articulates 
with  the  anterior  edge  of  the  process  described  on  the  inner  side  of  the  squamosal. 

The  supraoccipital  is  a  small  triangular  bone  which  in  the  specimen  is  separate 
from  the  exoccipital-opisthotic  on  the  left  side,  so  that  the  outline  is  plain. 

The  exoccipitals  are  separated  from  the  basioccipital  by  distinct  sutures,  but  are 
still  in  position.  The  lower  portions  meet  in  the  median  line,  excluding  the  basioccipital 
from  any  part  in  the  floor  of  the  foramen  mangum,  at  least  its  posterior  part.  There 
is  no  suture  visible  between  the  exoccipitals  and  the  opisthotics. 

The  opisthotics  are  expanded  at  the  inner  end,  where  they  contain  a  portion  of 
the  cavity  of  the  inner  ear.  Beyond  the  exoccipital  portion  they  contract  rapidly,  and 
the  outer  half  is  spatulate  in  form,  with  the  outer  end  reaching  to  the  extreme  outer 
edge  of  the  squamosal,  but,  in  the  specimen,  not  visible  in  a  lateral  view  of  the  skull. 
The  lower  edge  of  the  inner  third  is  marked  by  a  distinct  groove,  which  evidently 
protected  the  stapes  in  part.  This  groove  becomes  deeper  toward  the  inner  end  and 
is  continued  on  the  lower  edge  of  the  prootic. 

The  squamosals. — The  inner  side  of  the  squamosal  is  best  seen  from  the  posterior 
surface.  This  face  is  nearly  vertical,  but  is  divided  by  a  horizontal  ridge  which  originates 
near  the  posterior  end  and,  growing  more  prominent  as  it  advances,  terminates  near  the 
middle  of  the  length  of  the  squamosal.  To  the  anterior  end  of  this  ridge  is  articulated 
the  distal  end  of  the  parietal.  Immediately  below  the  ridge  lies  the  distal  end  of  the 
opisthotic,  which  is  here  a  narrow,  oval  plate  with  its  greatest  diameter  nearly  vertical. 
The  extremity  of  the  opisthotic  reaches  nearly  to  the  posterior  end  of  the  descending 
process  from  the  squamosal,  but  is  not  visible  from  the  outer  side.  The  upper  outer 
corner  of  the  quadrate  articulates  with  the  squamosal  by  a  rounded  head  just  anterior 
to  the  end  of  the  ridge  described  on  the  inner  surface  of  the  squamosal. 

The  quadrates. — These  are  much  as  described  in  other  specimens.  Each  quadrate 
stands  upright  in  the  skull,  with  a  broad  posterior  face,  which  contracts  toward  its 


64  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

upper  extremity.  The  articular  face  for  the  lower  jaw  is  convex  antero-posteriorly  and 
divided  into  two  parts  by  a  sharp  median  elevation  which  runs  obliquely  from  within 
outward  and  backward.  The  suture  with  the  quadratojugal  is  vertical  and  nearly 
straight,  running  from  the  lower  extremity  of  the  bone  nearly  to  the  top.  There  is 
a  large  quadrate  foramen  at  about  the  middle  point  of  the  suture,  which  runs  slightly 
downward  and  forward.  On  the  inner  face  there  is  a  slight  concavity  just  above  the 
articular  surface  and  then  a  strong  spout-like  process,  concave  downward,  which  extends 
forward  for  a  short  distance,  but  not  nearly  so  far  as  is  indicated  by  v.  Huene  in  M. 
•pleiningeri.  The  inner  edge  of  this  process  rises  gradually,  shortening  as  it  rises,  and 
disappears  on  the  anterior  face  of  the  quadrate  at  about  the  middle  of  its  height.  At 
the  origin  of  this  process  and  above  and  outside  it  there  is  a  fairly  deep  pit.  The  posterior 
edge  of  the  quadrate  process  of  the  pterygoid  fits  over  this  process  on  the  lower  and 
inner  side.  The  upper  portion  of  the  outer  edge  of  the  quadrate  is  inclined  inward 
slightly,  and  the  upper  extremity  terminates  in  a  smooth,  nearly  hemispherical  face 
which  fits  into  a  pit  on  the  lower  surface  of  the  squamosal.  There  can  be  no  doubt 
that  there  was  a  certain  amount  of  motion  possible  at  this  point,  which  would  be  per- 
mitted by  the  sliding  of  the  quadrate  process  of  the  pterygoid  on  the  spout-like  process 
of  the  quadrate.  This  reveals  a  greater  flexibility  of  the  posterior  portion  of  the  skull 
of  the  Parasuchia  than  has  previously  been  suspected.  Versluys1  regarded  the  skull  of 
the  Parasuchia  as  akinetic,  but  there  is  a  possibility  of  movement  between  the  parietal 
and  supraoccipital  and  a  possibility  of  movement  of  the  pterygoids  on  the  basipterygoid 
processes  of  the  basisphenoid ;  these  possibilities,  taken  with  the  evidence  of  the  movable 
quadrate  and  the  smooth  face  between  the  pterygoid  and  the  transverse,  indicate  that 
the  skull  of  the  Parasuchia  was  certainly  kinetic. 

The  lower  surface  of  the  skull. — In  this  portion  of  the  discussion  is  included  the 
description  of  the  walls  of  the  brain-case  and  the  narial  region. 

The  basioccipital-basisphenoid. — On  the  lower  surface  the  basioccipital  differs 
decidedly  from  specimens  Nos.  7261  and  7505,  described  on  a  later  page.  In  these 
specimens  the  lower  surface  of  the  neck  of  the  condyle  is  smooth  and  rounded,  without 
any  ridges  running  forward  to  the  tubera  basioccipitalia.  In  No.  7522  the  lower  surface 
of  the  neck  is  flat,  with  two  prominent  rounded  ridges  on  the  sides  of  the  neck  running 
from  the  condyle  to  the  tubera.  This  forms  a  decided  concave  area  with  a  nearly  flat 
bottom,  but  a  little  more  depressed  on  the  sides.  A  similar  condition  is  indicated  in 
the  imperfect  specimen,  No.  7474. 

The  tubera  are  prominent  and  formed  by  the  basioccipital  and  basisphenoid. 
The  basipterygoid  processes  are  well  formed  and  project  outward,  downward,  and 
forward;  at  the  posterior  end  of  each  there  is  a  sharp,  low  prominence;  such  prominences 
are  described  in  No.  7257,  and  their  position  is  indicated  in  the  other  specimens  by  more 
or  less  evident  areas  of  slight  rugosity.  The  space  between  the  basipterygoid  processes 
is  occupied  by  a  low,  sharp  ridge  which  is  continuous  with  the  very  sharp  lower  edge 
of  the  parasphenoid  rostrum.  This  condition  is  quite  different  from  the  other  spec- 
imens. In  No.  7257  the  space  is  occupied  by  three  ridges;  the  middle  one,  somewhat 
asymmetrically  placed  on  the  right  side,  was  probably  continuous  with  the  lower  edge 
of  the  parasphenoid  rostrum;  in  No.  7261  there  are  faint  ridges  on  each  side  and  no 
median  ridge;  in  No.  7505  there  is  the  faint  beginning  of  a  median  ridge;  in  No.  7474 
the  region  is  not  preserved. 

The  parasphenoid  rostrum  starts  to  rise  almost  directly  upward  in  the  skull;  the 
proximal  portion  of  the  lower  edge  is  nearly  at  right  angles  to  the  line  of  the  basicranial 
axis,  but  quickly  assumes  a  horizontal  position.  The  lower  edge  is  very  sharp.  There 

1  Versluys,  J.,  Zoologischer  Jahrbuch,  supplement  xv,  2  Band,  s.  647,  1912. 


CASE 


PLATE  12 


A.  Lower  surface  of  sacrum  of  a  phytosaur,  No.  7266,  U.  of  Mich.     X0.3. 

B.  Upper  surface  of  the  sacrum  shown  in  A. 

< '.    l.iiteral  view  of  the  liasirranium  of  a  phytosaur,  No.  7261,  U.  of  Mich.     X0.72. 

D.  Posterior  view  of  the  basicraniurn  of  a  phytosaur,  No.  7474.     X0.75. 

K.   I'pper  surface  of  a  basieranium  of  a  phytosaur,  No.  7505,  U.  of  Mich.     X0.67. 

F.  Outer  surface  of  the  ilium  of  a  phytosaur,  No.  7333,  U.  of  Mich.     X0.38. 

G.  Lower  surface  of  snout  of  a  phytosaur,  No.  7505,  U.  of  Mich.     X0.36. 


THE   UPPER   TRIASSIC    OF   WESTERN   TEXAS.  65 

is  no  indication  of  a  composite  structure  of  the  rostrum,  i.  e.,  a  presphenoid  and  a 
parasphonoid  portion,  as  described  by  Huene  in  M.  plieningeri. 

The  side  of  the  basioccipital-basisphenoid.~The  structure  of  the  sides  of  these 
bones  coincides  very  closely  with  those  described  in  other  specimens.  Between  the 
ridge  connecting  the  side  of  the  condyle  with  the  tubera  and  the  suture  between  the 
basioccipital  and  basisphenoid  there  is  a  deep  groove  passing  upward  and  terminating, 
apparently,  in  the  otic  opening.  Just  posterior  to  the  upper  end  of  this  groove  and  in 
the  exoccipital  bones,  which  are  in  place,  there  are  two  foramina — a  posterior,  larger  for 
the  exit  of  the  XII  nerve,  and  an  anterior,  smaller,  which  probably  transmitted  the 
IX,  X,  and  XL  Between  the  tubera  and  the  basipterygoid  process,  on  each  side,  are 
the  openings  of  the  foramina  for  the  internal  carotid  arteries,  which  open  into  the  base 
of  the  small  hypophysial  cavity. 

The  upper  surface  of  the  basioccipital-basisphenoid. — The  exoccipitals  come  together 
below,  forming  the  floor  of  the  foramen  magnum;  anterior  to  these  can  be  seen  the  very 
distinct  suture  between  the  basisoccipital  and  basisphenoid.  On  the  right  side  this 
suture  terminates  in  a  deep  pit  entirely  upon  the  upper  surface  of  the  bones.  The 
left  side  is  partly  obscured  by  the  prootic,  but  the  pit  is  apparently  present,  showing 
that  its  occurrence  on  the  right  side  is  normal.  The  presence  of  the  pit  can  not  be 
confirmed  from  other  specimens,  but  its  presence  is  suggested  in  No.  7505.  The  sella 
liircia  is  prominent  just  posterior  to  the  hypophysial  pit.  On  either  side  of  the 
pit  the  edges  of  the  basisphenoid  are  thickened,  forming  a  strong  articulation  with  the 
prootic. 

The  prootics.—The  prootic  of  the  left  side  is  in  place;  that  of  the  right  side  was 
found  detached,  but  it  fits  well  into  its  position.  The  posterior  portion  extends  back- 
ward in  a  point  for  some  distance,  and  articulates  with  the  opisthotic  both  above  and 
below;  an  epiotic  is  not  distinguishable  as  a  separate  element.  The  upper  edge  is 
thickened  for  attachment  to  the  parietal,  and  the  lower  and  anterior  edges  are  thickened 
for  attachment  to  the  basisphenoid.  Near  the  anterior  end  is  the  foramen  for  the 
V  nerve;  this  is  a  vertical  oval  with  the  greatest  diameter  nearly  twice  as  long  as  the 
horizontal  diameter.  The  portion  of  the  bone  anterior  to  the  large  foramen  is  bent 
inward  nearly  at  right  angles,  to  form  the  anterior  wall  of  the  brain-case.  The  two 
bones  do  not  meet  in  the  median  line.  On  the  anterior  face  of  this  portion  of  the  bone, 
at  about  the  level  of  the  lower  edge  of  the  large  foramen  (in  the  undistorted  bone  of 
the  right  side),  there  is  a  small  foramen  which  probably  transmitted  a  branch  of  the  V. 
On  the  inner  side  of  the  prootic,  posterior  to  the  large  foramen,  is  a  large  and  deep  pit 
which  sheltered  a  portion  of  the  inner  ear.  When  the  bone  is  in  position  this  pit  comes 
into  close  association  with  two  pits  on  the  anterior  inner  end  of  the  opisthotic  and  the 
large  pit  on  the  suture  between  the  basioccipital  and  basisphenoid.  On  the  lower  edge 
there  is  a  groove  continuous  with  the  groove  on  the  lower  edge  of  the  opisthotic. 

The  pterygoids  show  the  usual  tripartite  form,  but  are  rather  different  in  shape 
from  that  common  to  most  of  the  reptiles.  The  middle  portion  of  the  bone  is  thickened 
and  has  a  decided  notch  which  fits,  loosely,  the  basipterygoid  process  of  the  basisphenoid. 
The  quadrate  process  is  a  thin  plate  standing  nearly  vertical  in  the  skull,  which  extends 
backward  and  slightly  outward  and  articulates  with  the  pterygoid  process  on  the 
inner  side  of  the  quadrate.  The  outer  process  is  fairly  heavy.  Its  anterior  edge  is 
deeply  concave,  giving  the  whole  process  a  distinctly  crescentic  form.  The  process 
extends  outward,  downward,  and  backward.  The  distal  end  is  broad  and  very  thin 
and  lies  upon  the  upper  surface  of  the  distal  portion  of  the  transverse,  meeting  it  by 
a  very  smooth,  flat  surface  which  undoubtedly  permitted  free  movement.  The 
anterior  process  extends  forward  and  quickly  becomes  a  thin  vertical  plate.  In  the 


66  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

specimen  this  plate  lies  directly  in  contact  with  the  parasphenoid  process  and  rises 
considerably  above  it,  but  not  so  high  as  figured  by  v.  Huene.1 

The  upper  edge  of  the  pterygoid  rises  slowly,  forward,  from  the  median  portion 
and  passes  above  the  upper  edge  of  the  parasphenoid  process  at  about  its  middle  point. 
The  anterior  portions  of  the  pterygoids  are  joined  at  their  lower  edges,  forming  a  V,  which 
lies  between  the  anterior  portions  of  the  palatines. 

The  epipterygoid. — There  is  no  evidence  of  an  epipterygoid,  either  of  a  separate  bone 
or  of  an  articular  space  upon  the  pterygoid.  If  such  a  bone  were  present,  as  figured  by 
Huene,2  it  is  remarkable  that  no  evidence  remains  in  a  specimen  otherwise  so  complete. 

The  transverse.— This  bone  is  radically  different,  both  in  position  and  form,  from 
the  conception  which  has  been  derived  from  the  study  of  crushed  specimens.  It 
stands  nearly  vertical  in  the  skull,  slanting  slightly  backward  as  it  descends.  The  upper 
end  is  attached  to  the  maxillary  and  the  jugal.  The  upper  portion  of  the  shaft  is  a 
rather  thin  oval  in  section.  Below,  the  bone  becomes  broader  and  thicker,  with  a 
prominent,  heavy  supporting  ridge  on  the  lower  surface.  The  upper  surface  of  the 
distal  end  is  smooth  and  flat,  meeting  a  similar  face  on  the  pterygoid.  The  anterior 
outer  edge  of  the  smooth  face  of  the  transverse  is  terminated  by  an  elevated  shoulder 
which  limited  the  direction  of  motion  between  the  bones.  The  palatine  was  attached 
to  the  posterior  end  of  the  inner  side  of  the  transverse  by  a  close  suture,  forming  a  rigid 
joint;  this  fixed  the  transverse  in  its  position  and  allowed  motion  in  the  pterygoid  only. 
The  transverse  forms  the  greater  portion  of  the  descending  process  of  the  palatine 
region;  the  pterygoid  is  visible  from  the  side  only  as  the  thin  edge  of  the  distal  portion 
of  the  descending  process. 

On  the  inner  side  of  the  jugal,  or  the  jugal  and  the  post-orbital,  there  is  a  thin, 
prominent  extension  of  the  bone  which  forms  the  anterior  border  of  the  lateral  temporal 
opening;  this  gives  the  bone  an  L-shaped  section  and  contributes  largely  to  its  strength. 
The  lower  portion  of  this  extension  becomes  quite  heavy  just  posterior  to  the  last  of  the 
maxillary  teeth  and  is  penetrated  by  a  large  foramen  running  antero-posteriorly  for  a 
short  distance.  The  transverse  is  attached  just  below  this  heavy  extension.  Just 
anterior  to  its  attachment  to  the  distal  end  of  the  palatine  the  transverse  is  free  for  a 
short  distance,  but  the  bones  are  united  again,  leaving  a  small  palatine  fenestra  opposite 
the  middle  of  the  shaft  of  the  transverse. 

The  palatines  are  rather  heavy  posteriorly,  where  they  unite  with  the  transverse, 
but  soon  become  more  thin  and  plate-like.  The  median  portion  of  the  palatine  is  thicker, 
and  this  portion  forms  the  characteristic  ridge  on  the  lower  surface  of  the  palate  and  the 
outer  edges  of  the  choana?.  On  the  inner  side  of  the  heavier  portion  is  the  shoulder 
described  and  figured  by  v.  Huene  as  supporting  the  lower  edge  of  the  pterygoid.  The 
palatine  sends  out  two  very  thin  extensions:  an  upper,  which  overlies  the  pterygoids 
for  a  short  distance,  not  nearly  so  much  as  is  indicated  by  v.  Huene,  and  an  outer,  which 
unites  with  the  palatine  plate  of  the  maxillary.  The  upper  plate  forms  the  posterior 
and  outer  borders  of  the  choanse.  Near  the  middle  of  the  plate  there  is  a  strong  vertical 
ridge  which  ends  upon  a  prominence  upon  the  upper  edge.  Just  anterior  to  this  ridge 
the  palatine  divides  into  two  vertical  plates.  The  upper  edge  of  the  inner  plate  descends 
rapidly  and  soon  joins  its  fellow  of  the  opposite  side,  leaving  a  shallow  V-shaped  channel 
on  the  upper  surface;  the  two  together  form  the  septum  which  divides  the  choanae. 
The  outer  plate  runs  forward  and  joins  the  premaxillaries.  The  lower,  or  horizontal, 
plate  of  the  palatine  is  deeply  concave  just  below  the  heavier  median  portion,  forming  a 
channel  which  runs  as  far  forward  as  the  anterior  end  of  the  choanse.  This  channel 

1  Huene,  F.  v.,  Beitriige  zur  Kenntnis  und  Beurtheilung  der  Parasuchier,  Geol.  u.  Paleont.  Abhandlungen, 

N.  F.,  Bd.  x,  fig.  4,  1911. 

2  Huene,  F.  v.,  loc.  cit.,  figs.  5  and  0. 


TIIK    ri'I'KK    TRIASSIC    OF    WESTERN    TKXAS. 


67 


may  he  somewhat  exaggerated  by  pressure  in  the  specimen,  but  even  in  the  normal 
skull  it  was  a  prominent  feature. 

The  i'n  in  <  ;'x  do  not  appear  upon  the  lower  surface  of  the  skull.  This  is  very  different 
from  the  condition  of  the  palate  as  figured  by  the  various  authors  in  the  described  forms. 
It  seems  probable  that  the  interpretation  of  the  vomer  as  appearing  on  the  lower  surface 
of  the  skull  is  due  to  the  condition  of  the  specimens.  In  the  deep  V  formed  by  the  approxi- 
mation of  the  pterygoids  in  their  anterior  portions  there  is  evidence  of  a  pair  of  very 
slender  bones  which  have  the  same  relations,  i.  e.,  they  meet  below  to  form  a  V;  these 
are  apparently  the  much-reduced  vcmers.  The  position  and  reduced  condition  of  the 
vomers,  the  articulation  of  the  palatine  with  the  anterior  bones  of  the  roof  of  the  mouth, 
in  this  case  the  premaxillaries,  and  the  elevation  of  the  pterygoids  are  very  suggestive 
of  the  condition  in  the  Crocodilid. 


I+Ps 


LepUtsufhus  crosbiensis. 


FIG.  26. 

Left  side  with  outer  hones  removed  to  show  the  .structure  of  internal  nares. 
Lettering  as  usual. 


X  0.8. 


The  choance.  —  The  openings  of  the  internal  nares  are  separated  by  a  bar  composed 
of  the  palatines,  pterygoids,  and  probably  the  vomers.  There  was  a  distinct  space 
between  the  internasal  septum  of  the  external  nares  and  the  septum  between  the  choanai 
below.  Huene's  description  of  this  region  is  fairly  accurate,  but  he  has  not  recognized 
the  exact  relations  of  the  pterygoids,  palatine,  and  vomers,  and  has  not  recognized 
that  the  palatines  extend  forward  to  meet  the  premaxillaries.  The  bar  between  the 
choana>  is  formed  by  three  bones,  all  paired.  The  lower  pair  is  the  palatine  portion. 
These  bones  gradually  approximate;  the  posterior  portion  of  the  bar  is  V-shaped,  the 
anterior  portion  a  complete  oval  bar  with  a  complete  upper  edge.  Between  the  arms  of 
the  V  formed  by  the  palatines  there  is  a  second  V  formed  by  the  anterior  portion  of  the 
pterygoids.  which  retain  this  form  to  the  interior  end  The  lower  edge  of  the  pterygoid 
V  rests  upon  the  upper  edge  of  the  palatine  bar  at  the  extreme  anterior  end.  Between 
the  arms  of  the  V  formed  by  the  pterygoids  there  is  evidence  of  a  third  V,  formed  by 
the  vomers. 

The  m<i.r  ilttiric.  s-.-  -The  alveolar  edge  of  the  maxillaries  i<  supported  on  the  inner 
side  by  a  strong,  horizontal  palatine  plate.  There  are  21  sockets  in  the  maxillary,  the 
anterior  of  which  are  rounded  in  section,  but  the  posterior  10,  or  more,  are  oval.  The 
.-trong  median  prominences  on  the  premaxillaries  gradually  die  out  upon  the  palatine 
processes  of  the  maxillary. 

The  preiiHu-illtirics.—Tlie  anterior  end  of  the  premaxillary  is  but  slightly  expanded; 
it  accommodates  two  enlarged  sockets  for  the  tusk-like  anterior  teeth.  Posterior  to 


68  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

these  sockets  the  premaxillary  narrows,  and  there  are  three  small  sockets,  rather  on  the 
side  of  the  bone  than  on  its  lower  surface.  There  are  23  sockets  in  the  premaxillary;  in 
the  anterior  portion  these  are  rather  more  on  the  side  of  the  bone,  but  by  the  middle  of 
the  series  they  come  to  lie  entirely  on  the  lower  surface.  The  middle  of  the  snout  is 
occupied  by  the  two  prominent  rounded  ridges  which  are  considered  to  have  acted  as 
buffers  to  prevent  injury  to  the  jaws  when  they  were  snapped  violently  together. 

The  second  skull  (Leptosuchus  imperfecta,  No.  7523,  University  of  Michigan) 
is  much  larger  than  the  first,  measuring  approximately  112  cm.  over  all.  There  is  a 
break  in  the  continuity  of  the  snout,  and  it  is  impossible  to  determine  the  exact  length, 
though  only  a  very  small  part,  if  any,  can  be  missing.  The  whole  skull  seems  propor- 
tionately stouter  than  that  of  the  smaller  skull.  As  certain  portions  must  be  restored, 
it  is  desirable  to  designate  this  as  a  new  species  only  tentatively,  until  more  detailed 
study  can  be  made.  One  very  remarkable  feature  appears  in  this  skull:  There  is  an 
elevation  on  the  upper  surface  of  the  snout,  somewhat  farther  back  than  in  the  others 
in  the  collection.  This  elevation  is  decidedly  rugose  and  its  upper  surface  is  excavated 
by  a  nearly  hemispherical  pit  with  a  smooth  inner  surface.  The  pit  is  5  cm.  long  and 
4  cm.  wide,  extending  into  the  symphysis  of  the  premaxillary  bones.  The  condition  is 
so  remarkable  and  unexpected  that  the  pit  was  at  first  taken  for  the  opening  of  the 
external  nares,  but  this  is  easily  demonstrated  to  be  impossible,  v.  Huene1  described 
a  somewhat  similar  condition  in  a  specimen  of  M.  pleiningeri.  There  is,  in  his  speci- 
men, a  rough  area  near  the  anterior  end,  which  he  attributed  to  a  fracture  or  injury. 
In  the  center  of  this  rough  area  he  found  a  nodule  of  matrix.  From  the  evidence  cited 
in  this  paper  it  is  apparent  that  an  elevation  on  the  premaxillary  portion  of  the  snout  of 
members  of  the  Mystriosuchid  group  of  Phytosaurs  is  a  normal  thing,  but  in  none  of 
the  other  specimens  is  there  any  evidence  of  a  pit.  The  region  of  the  snout  surround- 
ing the  pit  is  rugose,  but  without  any  evidence  of  fracture  or  injury.  The  meaning 
of  this  apparent  abnormality  is  at  present  entirely  conjectural. 

Contrasting  characters  in  the  skulls  of  the  known  Phytosaurs.* 
Paleorhinus: 

1.  Post-temporal  arcade  depressed. 

2.  Antorbital  opening  posterior  to  the  external  nares  rounded. 

3.  Length  of  the  prenarial  portion  of  skull  is  to  the  postnarial  portion  as  1  +  :  1. 

4.  Post-temporal  fenestra  small. 

5.  Posterior  bar  of  parietal  short. 

6.  External  nares  with  elevated  rim;  internal  nares  posterior  to  external. 

7.  Squamosals  not  greatly  extended  behind. 

8.  Orbits  look  up  and  out. 

9.  Septomaxillary  (?). 

10.  Premaxillary  and  maxillary  teeth  36,  rounded  in  section. 

11.  Palatines  with  inner  edge  elevated  into  a  ridge.     Palatine  vacuity  anterior  to  the  middle  of  the  transverse. 

12.  Transverse  overlaps  the  external  pterygoid  process  below. 

13.  Vomers  extend  back  to  interpterygoid  vacuity. 

14.  Parasphenoid  process  short  (?). 

15.  Interpterygoid  vacuity  small. 
A  ngistorhinus: 

1.  Post-temporal  arcade  at  the  level  of  the  top  of  the  skull. 

2.  Antorbital  opening  with  the  anterior  end  even  with  the  anterior  end  of  the  external  nares.     Oval.     Anterior 

end  acute,  posterior  end  rounded. 

3.  Length  of  the  prenarial  portion  of  the  skull  is  to  the  postnarial  as  5  :  3. 

4.  Post-temporal  fenestra  largest  of  any  known  form. 

5.  Posterior  bar  of  the  parietal  very  short. 

6.  External  nares  with  elevated  rim,  low  septum;  internal  nares  a  little  posterior  to  the  external. 

7.  Squamosal  considerably  extended  backward  and  with  a  strong  descending  hook;  overhangs  the  bones  below. 

8.  Orbits  look  upward  more  than  outward. 

1  Huene,  F.  v.,  Beitrage    zur  Kenntnis   und  Beurtheilung    der  Parasuchier,  Geolog.  u.  Paleontlg.  Abhand- 

lungen,  N.  F.,  Bd.  x,  s.  5,  fig.  2,  1911. 

2  The  same  character  is  described  under  the  same  number  under  each  genus.     The  characters  given  are  as 

described  by  the  authors.     Some  of  these  must  be  modified  by  further  study.     The  probable  errors  are 
in  the  description  of  the  palatal  region. 


THE    UPPER   TRIASSIC   OF   WESTERN   TEXAS.  59 

9.  Septomaxillary  present. 

10.  Premaxillary  and  maxillary  teeth,  41  ±,  round  and  oval,  with  serrate  edges. 

11.  Palatine  with  inner  edge  elevated  into  a  ridge.     The  palatine  vacuity  between  the  palatine,  pterygoid,  and 

the  anterior  half  of  the  transverse. 

12.  Transverse  meets  the  external  edge  of  the  pterygoid.     No  external  process  of  the  pterygoid. 

13.  Vomers  do  not  appear  behind  the  internal  nares. 

14.  Parasphenoid  process  long,  covered  anteriorly  by  the  pterygoids. 

15.  Interpterygoid  vacuity  short,  narrow. 
Phytosaunts  (Machaeroprosopus): 

1.  Post-temporal  arcade  depressed;  not  visible  from  above. 

2.  Anterior  end  of  the  antorbital  vacuity  anterior  to  the  external  nares;  elongate  oval. 

3.  Length  of  the  prenarial  portion  of  the  skull  is  to  the  postnarial  as  3  :  2. 

4.  Post-temporal  fenestra  large. 

5.  No  posterior  bar  on  the  parietal;  the  postorbital  takes  the  place  of  the  parietal  on  the  posterior  edge  of 

the  skull. 

6.  External  nares  without  elevated  rim,  septum  at  the  level  of  the  top. 

7.  Squamosal  region  greatly  extended  posteriorly,  with  a  strong  hook. 

8.  Orbits  look  outward  more  than  upward;  slightly  forward. 

9.  Septomaxillaries  large,  united  in  front  and  form  a  prominence,  "if  correctly  determined"  (Mehl). 

10.  Premaxillary  and  maxillary  teeth  36-38;  both  rounded  and  oval  in  section. 

11.  Palatal  surface  of  the  skull  unknown. 
Mystriasuchus: 

1.  Post-temporal  arcade  depressed. 

2.  Anterior  end  of  antorbital  opening  anterior  to  the  nares;  nares  over  the  middle  of  the  opening. 

3.  Length  of  the  prenarial  portion  of  the  skull  is  to  the  postnarial  as  5  :  2. 

4.  Post-temporal  fenestra  small. 

5.  Posterior  bar  of  the  parietal  depressed,  lying  on  the  opisthotic,  long. 

6.  External  nares  with  elevated  rim,  septum  at  upper  level;  internal  nares  directly  under  the  external  nares. 

7.  Squamosal  region  extended  posteriorly. 

8.  Orbits  look  outward  more  than  upward;  upward  in  M.  pleiningeri. 

9.  Septomaxillary  present. 

10.  Premaxillary  and  maxillary  teeth  47-50,  both  rounded  and  oval  in  section. 

11.  Inner  edge  of  palatine  elevated;  palatine  vacuity  opposite  the  middle  of  the  transverse. 

12.  Transverse  underlies  the  external  process  of  the  pterygoid. 

13.  Vomers  do  not  extend  posterior  to  the  internal  nares,  or  very  little. 

14.  Parasphenoid  process  fairly  long,  anterior  end  covered. 

15.  Interpterygoid  vacuity  small. 
Promystriositchus: 

1.  Post-temporal  arcade  at  the  level  of  the  skull. 

2.  Anterior  end  of  the  antorbital  opening  opposite  middle  of  external  nares;  elongate  oval. 

3.  Length  of  prenarial  portion  of  the  skull  is  to  the  postnarial  portion  as  3  :  2. 

4.  Post-temporal  foramen  small. 

5.  Posterior  bar  of  the  parietal  long. 

6.  Rim  of  external  nares  elevated,  septum  low;  position  of  the  internal  nares  posterior  to  external. 

7.  Squamosal  region  not  greatly  extended  posteriorly. 

8.  Orbits  look  upward,  perhaps  in  part  due  to  crushing. 

9.  Septomaxillary  (?). 

10.  Premaxillary  and  maxillary  teeth  47;  both  oval  and  rounded  in  section. 

11.  Inner  edge  of  palatine  raised  and  rugose.     Palatine  vacuity  small,  near  middle  of  transverse. 

12.  Transverse  underlies  the  outer  process  of  the  pterygoid. 

13.  Vomers  (?). 

14.  Parasphenoid  process  long;  anterior  end  probably  covered  by  the  pterygoids. 

15.  Interpterygoid  vacuity  long. 
Leptosuchus: 

1.  PosMemporal  arcade  depressed. 

2.  Antorbital  opening  with  the  anterior  end  even  with  the  anterior  end  of  the  nares;  oval  in  outline. 

3.  Length  of  the  prenarial  portion  of  the  skull  is  to  postnarial  portion  as  3  :  2. 

4.  Post-temporal  fenestra  small. 

5.  Posterior  bar  of  the  parietal  long,  lying  on  the  opisthotic. 

6.  External  nares  without  rim,  septum  at  level  of  the  skull.     Internal  nares  directly  below  the  external. 

7.  Squamosal  extended  posteriorly  with  a  strong  descending  process;  overhanging  the  tones  below. 

8.  Septomaxillary  present. 

9.  Orbits  look  upward  and  outward. 

10.  Premaxillary  arid  maxillary  teeth  44;  both  rounded  and  oval  in  section. 

11.  Inner  edge  of  palatine  strong,  a  low  ridge;  palatine  foramen  small,  opposite  middle  of  transverse. 

12.  Transverse  underlies  the  pterygoid. 

13.  Vomers  do  not  appear  on  the  palatal  surface. 

14.  Parasphenoid  process  long,  covered  anteriorly  by  the  pterygoids. 

15.  Interpterygoid  space  short  and  narrow. 


70  NEW   REPTILES    AND    STEGOCEPHALIANS    FROM 

DESCRIPTION   OF  ISOLATED   BONES  OF  PARASUCHIANS. 

Many  isolated  bones  were  found  in  the  beds  in  Crosby  County,  Texas,  and 
a  few  in  the  Bad  Lands  west  of  San  Jon,  New  Mexico.  Some  of  these  are  described 
and  figured  below: 

An  interclavicle  (No.  7442,  University  of  Michigan)  found  by  Mr.  Paul  Miller 
in  the  Bad  Lands  5  miles  west  of  San  Jon,  New  Mexico,  resemble.?  in  general  the  inter- 
clavicle  of  Mystriosuchus  planirostris,  figured  by  McGregor.1  The  blade  is  stouter  and 
the  articular  faces  for  the  clavicles  are  deeper  and  larger.  The  anterior  portion  is  heavily 
rugose  on  the  lower  side,  and  the  dividing  septum  between  the  two  articular  faces  is 
elevated  and  strong.  The  distal  end  is  incomplete,  but  enough  is  preserved  to  show  that 
the  whole  bone  was  shorter  and  wider  than  in  M.  planirostris.  The  upper  face  of  the 
blade  is  gently  convex  and  covered  by  fine  radiating  lines  in  the  posterior  half.  The 
lower  surface  of  the  bone  is  gently  convex  in  front,  but  the  posterior  half  is  nearly  flat. 
This  portion  is  marked  by  rough,  radiating  rugosities  imposed  upon  a  sculpture  of  very 
fine  lines.  The  whole  bone  is  216  mm.  long  as  preserved,  and  could  not  have  been  a  very 
great  deal  longer  when  complete  (fig.  27  A). 

A  second  interclavicle  (No.  7313,  University  of  Michigan)  was  found  in  the  same 
region;  it  is  very  imperfect,  but  indicates  the  presence  of  a  very  large  animal,  in  which 
the  posterior  extension  of  the  interclavicle  was  much  greater  than  in  the  one  described 
and  figured  above. 

There  are  five  ilia  and  partially  complete  pelves  (Nos.  7244,  7266,  7322,  7333, 
7470),  all  in  the  University  of  Michigan  collection.  Four  of  these  are  so  decidedly 
different  that  they  indicate  the  presence  of  different  forms  of  at  least  specific  value. 
They  are  described  separately  below. 

No.  7322  is  a  perfect  ilium  from  the  right  side,  discovered  in  the  breaks  of  Sand 
Creek,  Crosby  County,  Texas.  It  is  shown  in  figure  27  B;  plate  13,  figure  A.  The 
anterior  extension  of  the  upper  edge  is  somewhat  elongated  and  down-curved;  it  extends 
as  far  forward  as  the  articulation  of  the  lower  anterior  edge  of  the  ilium  with  the  pubis. 
This  hook-like  extension  is  rather  broad  above,  but  not  nearly  as  broad  as  in  some  of  the 
other  ilia.  The  lower  edge  of  the  posterior  extension  of  the  ilium  extends  forward  at  a 
gentle  angle  to  form  the  articulation  with  the  ischium.  The  extreme  posterior  edge 
of  this  slanting  surface  is  curved  inward,  giving  a  broad  posterior  face  inclined  backward 
and  outward.  The  cotylus  is  very  deep  and  the  faces  for  the  articulation  with  the  ischium 
and  pubis  meet  at  a  gentle  angle  or  on  the  surface  of  a  broad  curve.  The  upper  edge 
of  the  blade  is  moderately  broad,  and  the  anterior  face  of  the  blade  rises  almost  directly 
from  the  upper  edge  of  the  cotylus.  The  inner  face  is  somewhat  water-worn  and  the 
articulations  for  the  sacral  ribs  are  in  part  destroyed,  but  it  is  apparent  that  they  stood 
very  much  lower  upon  the  bone  than  in  other  specimens  and  that  the  whole  blade  of 
the  bone  was  more  slender. 

No.  7244,  also  from  Sand  Creek,  Crosby  County,  Texas,  is  very  different  in  form 
from  the  preceding  (fig.  27  c;  plate  13,  fig.  B).  The  anterior  process  of  the  blade  of 
the  ilium  is  very  short,  not  reaching  halfway  to  the  articulation  of  the  ilium  with 
the  pubis.  The  extremity  does  not  turn  downward  at  all,  but  is  directed  slightly  upward 
through  its  whole  length.  The  upper  edge  of  the  blade  is  relatively  thin  and  slightly 
rugose  on  its  anterior  face.  The  whole  blade  is  more  than  twice  as  thick  as  in  the 
preceding  specimen,  for  on  the  inner  side  of  the  bone  there  is  a  concave  area  looking 
inward  and  upward  before  the  articular  faces  for  the  sacral  vertebra;  begin.  The  posterior 
process  extends  almost  directly  backward:  from  the  articulation  with  the  ischium  the 

'  McGregor,  .1.  H..  Memoirs  American  Museum  Natural  History,  vol.  ix,  part  n,  fig.  9,  190(5. 


CASE 


PLATE   13 


inf-i 


cond 


D 


A.  Outer  surface  of  ilium  of  a  phytosatir,  No.  7322,  U.  of  Mich.     XO.ol. 

B.  Inner  .surface  of  ilium  of  a  phyt<»aur,  No.  7244,  U.  of  Mich.     X0.45. 

C.  A  plate  of  dorsal  armor  of  a  phytosaur  of  the  Mystriosuchid  group,  No.  7247,  U.  of  Mich.      X0.8. 

D.  The  cranial  region  of  skull  of  a  small  dinosaur,  Ccelophysis  sp.,  No.  7473,  U.  of  Mich.     X0.9. 

E.  Lower  view  of  I).         F.   Lateral  view  of  D. 

inf.,  cavity  for  infuiulilmlum;  ol.,  otic  region;  bpl.,  hasipterygokl  process  of  Iwisplirnoid;  fun!.,  orripitnl  condyle. 


THE   UPPER   TRIASSIC   OF   WESTERN   TEXAS. 


71 


lower  edge  runs  upward  and  forward  for  a  short  distance  and  then  turns  directly  back- 
ward. The  posterior  end  is  broken  away  and  lost;  so  the  total  length  of  the  process  is 
uncertain,  but  it  was  evidently  quite  long.  The  lower  edge  of  the  process  is  turned 
inward,  as  in  No.  7322,  but  in  this  specimen  it  looks  almost  directly  downward  rather 
than  down  and  back.  The  cotylus  is  not  so  deep  and  the  faces  for  the  ischium  and  pubis 
meet  in  a  sharp  angle.  On  the  inner  face  (see  plate  13,  fig.  B)  the  upper  part  of  the  blade 
of  the  ilium  is  deeply  concave;  the  lower  edge  of  the  concavity  marks  the  upper  edge  of 
the  articular  surface  for  the  sacral  ribs.  Near  the  anterior  end  there  are  two  deep, 


FIG.  27. 

A.  Lower  surface  of  interclavicle,  No.  7442,  U.  of  Mich.     X  0.3. 

B.  Right  ilium,  outer  side,  No.  7322,  U.  of  Mich.     X  0.3. 

C.  Left  ilium,  outer  side,  No.  7244,  U.  of  Mich.     X  0.3. 

D.  Left  ilium,  outer  side,  No.  7333,  U.  of  Mich.     X  0.3. 

E.  Left  ilium,  outer  side,  No.  7266,  U.  of  Mich.     X  0.3. 

rugose  pits  below  this  edge,  marking  the  place  of  insertion  of  the  distal  ends  of  the  sacral 
ribs.  Below  the  posterior  pit  there  is  a  wide  rugose  surface  which  received  the  posterior 
half  of  the  distal  end  of  the  second  rib.  Above  this  surface  the  lower  edge  of  the  concave 
surface  extends  back  as  far  as  the  posterior  end  of  the  broken  bone;  it  evidently  extended 
to  the  extremity  in  the  perfect  specimen.  The  whole  bone  is  much  heavier  than  in 
No.  7322,  the  anterior  edge  just  below  the  anterior  process  of  the  upper  edge  being  excep- 
tionally thick. 

No.  7333  differs  from  either  of  the  previously  described  forms  in  that  the  height 
is  much  less  relative  to  the  length  (fig.  27  D;  plate  12,  fig.  F).     The  length  of  the  anterior 


72  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

process  of  the  crest  is  intermediate  in  length  between  that  of  Nos.  7322  and  7244,  reaching 
about  halfway  to  the  articulation  with  the  pubis.  This  process  is  much  thinner  on  the 
upper  edge  even  than  No.  7322,  as  the  outer  side  is  beveled  by  a  rough  surface.  The 
posterior  process  is  relatively  much  longer  than  in  either  of  the  others  and  extends 
backward  with  much  the  same  slant  as  in  No.  7322.  The  posterior  extremity  is  thickened 
by  the  inward  curvature  of  the  lower  edge,  the  face  thus  formed  looking  almost  directly 
downward.  The  cotylus  is  exceptionally  deep,  as  there  is  a  strong  buttress  developed 
near  its  anterior  edge  which  maintains  its  width  to  the  upper  edge  of  the  bone.  The 
upper  edge  of  the  cotylus  is  extended  forward  on  the  anterior  portion  of  the  bone,  forming 
a  sharp  ridge  and  giving  the  whole  region,  and  the  articular  face  for  the  pubis,  a  triangular 
section.  The  articular  faces  for  the  ischium  and  the  pubis  are  exceptionally  heavy. 
On  the  inner  side  there  are  no  deep  cavities  for  the  articulation  of  the  distal  ends  of  the 
sacral  ribs.  The  upper  portion  of  the  blade  is  smooth  and  is  free  above  the  sacrum  for 
some  distance;  this  surface  is  only  gently  concave.  The  upper  edge  of  the  ilium  is 
thickened  at  the  anterior  and  posterior  edges,  but  the  median  portion  is  quite  thin  and 
sharp.  This  is  decidedly  different  from  the  two  other  forms  described,  where  the  upper 
edge  is  thick  and  heavy  throughout  its  length,  the  median  part  being  nearly  as  thick  as 
either  of  the  ends. 

No.  7266,  discovered  near  the  head  of  Holmes  Creek,  in  Crosby  County,  Texas, 
consists  of  the  two  ilia  and  the  sacral  vertebrae  complete,  except  for  the  neural  spines. 
The  specimen  has  been  slightly  crushed  from  above  downward,  but  not  enough  to  materi- 
ally distort  the  specimen.  The  ilia  are  similar  in  form  to  No.  7333,  but  nearly  twice 
as  large;  they  probably  belong  to  an  animal  of  the  same  species,  but  of  larger  size.  The 
anterior  process  of  the  blade  of  the  ilium  (fig.  27  E)  is  relatively  slender,  reaching  a  little 
more  than  halfway  to  the  articulation  with  the  pubis;  its  extremity  is  very  slightly 
down-curved.  The  posterior  process  is  long,  and  the  lower  edge  extends  backward, 
almost  directly  from  the  articulation  with  the  ischium,  at  a  gentle  angle.  The  cotylus 
is  deep,  especially  near  the  anterior  end,  where  there  is  a  strong  buttress  reaching  down 
from  the  upper  edge  of  the  bone  to  the  upper  edge  of  the  cotylus.  The  articular  edges 
for  the  ischium  and  pubis  meet  in  a  large  angle.  The  upper  edge  of  the  blade  is  relatively 
thin,  with  slight  thickenings  at  the  anterior  and  posterior  ends.  The  articular  portions 
of  these  edges  outside  of  the  cotylus  are  very  heavy.  The  slight  depression  of  the 
pelvis  has  thrown  the  lower  edges  of  the  ilia  inward  and  the  upper  edges  outward,  slightly, 
so  there  is  an  apparent  flattening  of  the  upper  surface.  The  blade  of  the  ilium  on  each 
side  rises  free  from  the  upper  surfaces  of  the  sacral  vertebrae,  and  there  is  a  decided 
concave  area  on  each  bone  on  the  inner  upper  side.  The  articulation  of  the  distal  ends 
of  the  sacral  ribs  is  close  and  firm,  the  anterior  one  being  received  in  deep  rugose  pits 
and  the  posterior  one  articulating  along  the  length  of  a  rather  heavy  ridge  (fig.  28  A; 
plate  12,  figs.  A  and  B). 

The  sacrum  is  formed  of  two  heavy  vertebra;;  the  neural  spines  have  been  destroyed 
and  the  neural  arches  are  pressed  downward,  almost  closing  the  neural  canal,  but  they 
were  not  high  even  in  the  undistorted  specimen.  The  two  vertebra}  were  not  anchylosed, 
even  in  this  evidently  adult  specimen,  and  the  zygapophyses  between  the  two  sacral 
vertebrae  are  still  well  formed  and  distinct,  though  somewhat  injured.  The  sacral  ribs  are 
very  wide  and  strong,  giving  a  powerful  attachment  of  the  pelvis  to  the  vertebral  column. 
The  ribs  originate  high  upon  the  sides  of  the  neural  arch,  almost  at  the  level  of  the  zyga- 
pophyses; there  is  no  indication  of  sutures  at  the  proximal  ends.  The  anterior  ribs 
originate  along  the  full  length  of  the  side  of  the  vertebrae,  the  anterior  edges  being  as  far 
forward  as  the  anterior  extremity  of  the  prezygapophysis,  and  the  posterior  edges  originat- 
ing relatively  as  far  back.  This  rib  is  very  heavy  at  its  proximal  end  and  becomes  more 
so  as  it  extends  outward  in  a  fan-shape;  the  distal  end  is  at  least  3  centimeters  thick 


THE    UPPER   TRIASSIC   OF   WESTERN   TEXAS. 


73 


where  it  fits  into  the  deep  pits  on  the  inner  side  of  the  ilium.  There  is  a  notch  on  the 
posterior  side  near  the  proximal  end  which  is  in  opposition  to  a  similar  notch  on  the 
anterior  side  of  the  proximal  end  of  the  second  rib,  leaving  an  opening  for  the  escape 
of  the  nerves  between  the  two  vertebrae.  The  anterior  rib  slightly  overlaps  the  posterior 
rib  at  the  distal  end. 

The  second  rib  is  nearly  as  large  at  its  origin  as  the  anterior  one,  but  the  neck  is 
somewhat  narrower,  due  to  the  presence  of  notches  on  the  anterior  and  posterior  edges. 
Its  anterior  edge  slants  somewhat  forward,  but  not  at  so  great  an  angle  as  the  posterior  edge, 
which  extends  back  to  the  extremity  of  the  posterior  process  of  the  blade  of  the  ilium. 
The  distal  end  is  not  so  much  thickened  as  in  the  anterior  rib,  and  the  posterior  portion 
of  the  distal  end  attaches  to  the  ridge  on  the  inner  side  of  the  ilium  by  an  overlap. 

Specimen  No.  7470  consists  of  the  nearly  entire  right  half  of  the  pelvis,  with  the 
two  sacral  vertebrae  and  several  associated  dorsals.  It  was  found  by  the  author  near 


Fio.  28. 

A.  Upper  surface  of  pelvis  and  sacrum,  No.  7266,  U.  of  Mich. 

B.  Right  side  of  pelvis,  No.  7470,  U.  of  Mich.     X  0.25. 


X  0.25. 


the  head  of  Holmes  Creek,  Crosby  County,  Texas.  The  posterior  half  of  the  ilium  has 
been  slightly  crushed  down  and  out,  and  the  distal  portion  of  the  pubis  is  lacking,  but 
the  ischial  portion  of  the  symphysis  is  complete  and  a  part  of  the  ischium  of  the  left 
side  is  preserved. 

The  form  of  the  ilium  (fig.  28  B)  is  most  like  that  of  No.  7322.  The  anterior  process 
is  long,  reaching  as  far  forward  as  the  articulation  with  the  pubis,  and  the  distal  end  is 
slightly  but  definitely  down-turned.  There  is  no  buttress  over  the  anterior  portion 
of  the  upper  edge  of  the  cotylus.  The  posterior  process  is  somewhat  distorted  by  the 
crushing  described  above,  but  it  is  apparent  that  its  lower  edge  rose  rather  abruptly, 
much  more  so  than  in  No.  7322. 

The  upper  edge  of  the  blade  of  the  ilium  is  decidedly  thickened,  more  at  the  anterior 
and  posterior  ends,  but  also  in  the  median  portion.  The  top  of  the  anterior  process  is 
wide  and  only  slightly  convex.  Near  the  extremity  of  the  posterior  end  there  is  a  very 
decided  thickening  of  the  bone,  due  to  the  development  on  the  outer  face  of  a  triangular 
prominence  resembling  the  buttress  which  is  described  upon  specimens  7333  and  7266, 
but  at  the  opposite  end  of  the  blade  of  the  ilium.  The  cotylus  is  very  deep  in  the  anterior 


74  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

upper  portion,  but  otherwise  it  is  more  shallow  than  in  any  other  of  the  specimens; 
this  may  be  in  part  due  to  the  distortion  of  the  specimen.  On  the  inner  side  there  is  a 
much  wider  area  above  the  place  of  the  attachment  of  the  distal  ends  of  the  sacral  ribs; 
the  anterior  rib  was  received  into  a  deep  rugose  pit,  as  in  specimen  7244,  and  the  posterior 
rib  was  attached  along  a  ridge  which  ran  backward  from  the  pit.  The  anterior  face 
of  the  lower  part  of  the  ilium  descends  toward  the  articulation  with  the  pubis  much 
more  directly  than  in  any  other  of  the  specimens. 

The  ischium  and  pubis  are  closely  anchylosed  with  the  ilium,  so  that  it  is  difficult 
to  follow  the  sutures.  The  anterior  edge  of  the  proximal  portion  of  the  pubis  continues 
almost  directly  downward  from  the  articulation  with  the  ilium;  just  below  the  artic- 
ulation there  is  a  large  pit  near  the  edge.  A  little  below  this,  and  in  the  lower  part 
of  the  cotylus,  is  the  opening  of  the  pubic  foramen.  The  distal  portion  of  the  pubis 
is  lost. 

The  posterior  edge  of  the  ischium  runs  downward  and  then  turns  sharply  forward, 
forming  the  upper  edge  of  a  narrow  but  strong  process.  The  symphysis  is  preserved 
forward  almost  to  the  juncture  of  the  ischium  with  the  pubis;  the  union  of  the  bones  of 
the  two  sides  is  strong,  as  they  meet  in  a  wide  articular  face  and  are  firmly  fastened 
together  in  the  specimen.  The  line  of  the  symphysis,  so  far  as  preserved,  is  sigmoid. 

The  sacrum  of  this  specimen  is  complete  and  resembles  that  of  No.  7266.  The 
anterior  rib  rises  from  the  level  of  the  zygapophyses  and  is  very  heavy;  the  rib  stands 
with  its  greatest  diameter  vertically,  which  is  perhaps  the  normal  position.  The  distal 
end  was  received  in  a  pit  on  the  inner  side  of  the  ilium.  The  two  vertebrae  are  separate 
and  the  zygapophyses  between  them  are  distinct  and  well  formed.  The  neural  spines 
of  the  vertebrae  are  complete  and  show  an  enlargement  of  the  upper  end,  forming  heavy 
flat  tables  which  overhang  the  sides  of  the  neural  spine.  The  upper  surface  of  the  tabular 
expansion  is  marked  by  a  shallow  depression  which  runs  antero-posteriorly. 

In  comparison  with  the  pelvis  of  Rhytidiodon  carolinensis,  as  figured  by  McGregor, 
Nos.  7333  and  7266  are  apparently  of  the  same  type  and  are  probably  Mystriosuchids, 
but  Nos.  7470,  7244,  and  7322  are  decidedly  different.  The  ischium  of  No.  7470  resembles 
that  of  R.  carolinensis,  but  the  posterior  (upper)  edge  is  perhaps  a  little  more  curved, 
the  symphysis  is  stronger,  and  the  lower  edge  of  the  symphysis  is  sigmoid  in  outline. 
There  is  no  suggestion  of  a  space  between  the  ischium  and  pubis,  filled  during  life  with 
cartilage;  the  two  halves  of  the  pelvis  meet  at  a  decided  angle,  and  there  could  have 
been  little  opportunity  for  a  median  vacuity.  The  pubis  is  largely  lost,  but  the  anterior 
edge  is  decidedly  convex  in  its  upper  portion,  suggesting  a  very  different  contour  from 
that  of  R.  carolinensis.  These  differences,  combined  with  the  shape  of  the  ilium,  suggest 
that  this  pelvis  belonged  to  some  member  of  the  Phytosaurid  group,  a  suggestion  borne 
out  by  the  few  plates  found  with  the  specimen  which  are  typically  phytosaurian.  The 
peculiar  outline  of  the  upper  part  of  the  anterior  edge  of  the  pubis,  suggesting  a  more 
vertical  position  of  the  anterior  face  of  the  pubis,  recalls  the  peculiar  pelvis  described  by 
Mehl,1  from  the  Triassic  of  New  Mexico,  as  Acompsosaurus  wingatensis,  and  even  more 
the  condition  found  in  the  Pseudosuchians  Ornilhosuchus  and  Euparkeria.  It  is  not 
supposed  that  the  resemblance  implies  genetic  relationships,  but  so  little  is  as  yet  known 
of  the  Triassic  reptiles  in  North  America  that  note  must  be  taken  of  suggested  resem- 
blances until  their  value  may  be  correctly  estimated.  In  v.  Meyer's  paper  upon  the 
Reptilia  of  the  Steuben  Sandstone  of  the  Upper  Keuper2  there  are  figured  three  phytosau- 
rian ilia.  Figure  1  has  much  the  same  form  as  Nos.  7333  and  7266,  described  and  figured 
above,  while  figure  5  resembles  more  closely  No.  7244.  Von  Meyer  did  not  assign  the 
ilia  figured  by  him  to  any  definite  genus  or  species. 

1  Mehl,  M.  G.,  Quarterly  Bulletin  of  the  University  of  Oklahoma,  new  series,  No.  103,  p.  33,  1916. 

2  Meyer,  H.  v.,  Paleontographica,  Bd.  7,  Taf.  41,  figs.  1,  3,  5. 


THE   UPPER   TRIASSIC   OF   WESTERN   TEXAS. 


75 


There  is  a  single  left  scapula  (No.  7472,  University  of  Michigan),  in  a  somewhat 
imperfect  condition,  the  proximal  end  being  slightly  injured  by  decay.  It  is  impossible 
to  give  the  exact  outline  of  the  anterior  edge  (see  fig.  29  A),  but  there  was  evidently  a  much 
greater  extension  of  the  region  than  in  Rhytiodon  carolinensis.  The  wide  extension  of 
the  anterior  lower  border  recalls  that  of  the  Permian  Pelycosauria  and  some  of  the 
South  African  Upper  Paleozoic  reptiles.  The  articular  face  for  the  coracoid  is  thick  and 
heavy.  The  distal  end  of  the  blade  was  broken  and  the  parts  somewhat  overthrust, 
but  making  allowance  for  this  the  total  length  was  277  mm.,  slightly  larger  than  R. 
carolinensis. 


FIG.  29. 

A.  Right  scapula,  No.  7472,  U.  of  Mich.     X  0.15. 

B.  Right  femur,  No.  3395,  U.  of  Mich.     X  0.15. 

C.  Right  humerus,  No.  7312,  U.  of  Mich.     X  0.15. 

D.  Right  radius,  No.  7312,  U.  of  Mich.     X  0.15. 

E.  Right  ulna,  No.  7312,  U.  of  Mich.     X  0.15. 

A  single  right  coracoid  (No.  7315,  University  of  Michigan)  is  too  imperfect  for 
figuring  or  description,  but  shows  the  presence  of  a  large  notch  on  the  anterior  edge. 

A  very  imperfect  scapula-coracoid  (No.  7471,  University  of  Michigan)  shows  only 
the  proximal  portions  and  the  outlines  of  the  cotylus.  Evidently  there  was  in  this 
specimen  the  same  large  expansion  of  the  anterior  lower  portion  of  the  scapula  as  in 
No.  7472,  but  the  size  of  the  preserved  portions  indicates  an  animal  at  least  one-half 
larger. 


76  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

There  are  two  femora  in  the  collection  (Nos.  7330  and  3395,  University  of  Michigan). 
The  first  is  a  very  small  femur  73.5  mm.  long,  apparently  of  an  immature  individual. 
The  articular  ends  are  imperfect,  as  if  incomplete  ossification  had  permitted  their  rapid 
decay.  The  trochanter  is  large  compared  to  that  in  larger  specimens  and  is  well  formed. 
The  second  femur  is  from  the  right  side  of  a  fairly  large  individual.  It  corresponds  in 
form  very  closely  with  that  of  R.  carolinensis  (fig.  29  B). 

In  one  small  spot  north  of  the  Spur-Crosbyton  road  the  remains  of  two  or  three 
large  Phytosaurs  were  found  in  close  proximity.  Most  of  the  bones  were  badly  weathered, 
but  a  humerus,  radius,  and  ulna  were  collected  in  close  association  and  in  good  condition. 
It  has  been  assumed  that  these  bones  belonged  to  one  individual,  as  they  are  of  the 
proper  size  and  of  the  same  side.  They  have  been  numbered  7312  in  the  University 
of  Michigan  collection. 

The  humerus  (fig.  29  c)  has  the  two  articular  ends  of  nearly  equal  breadth,  with  the 
long  axes  inclined  at  a  slight  angle  to  each  other.  The  deltoid  ridge  is  broken  away  in 
part,  but  stood  nearly  at  a  right  angle  to  the  proximal  end  of  the  bone.  The  shaft  is 
nearly  cylindrical.  The  lower  end  has  a  well-developed,  nearly  hemispherical  head  for 
the  radius  and  a  distinct  articular  surface  for  the  ulna.  There  is  a  distinct  ectepicondylar 
process  which  is  not  complete  in  the  specimen.  There  is  no  entepicondylar  notch 
or  foramen.  The  total  length  of  the  humerus  is  28.35  cm.;  the  breadth  of  the  upper 
end  is  14.2  cm.,  and  the  breadth  of  the  lower  end  12.7.  cm. 

The  radius  (fig.  29  D)  has  a  nearly  straight  cylindrical  shaft;  the  upper  end  has  a 
well-formed  concave  articular  surface;  the  lower  end  is  but  slightly  expanded.  The 
total  length  is  24.6  cm. 

The  ulna  (fig.  29  E)  is  very  broad  proximally  and  gradually  contracts  in  breadth  to 
the  lower  end.  The  shaft  is  compressed,  so  that  it  is  much  thinner  than  broad;  this 
may  be,  in  part,  due  to  compression.  The  articular  face  is  shallow,  and  there  is  a  very 
small  olecranon  process.  The  out  corner  of  the  lower  end  was  broken  away  and  lost 
and  has  been  restored  in  plaster.  The  total  length  of  the  ulna  is  30  cm. 

All  of  these  limb-bones,  as  well  as  the  femur  described  above,  and  the  remains  of 
less  perfect  limb-bones  in  the  collection  indicate  that  the  Phytosaurs  of  the  region  were 
relatively  long-limbed  forms  and  must  have  been  capable  of  raising  the  body  from  the 
ground  for  a  time  at  least,  and  also  that  they  were  capable  of  relatively  rapid  progression 
upon  the  land. 

There  are  in  the  University  of  Michigan  collection  four  basi-cranii  of  Phytosaurs, 
Nos.  7257,  7261,  7474,  and  7505.  The  first  three  show  the  condyle  complete,  the  last 
has  the  condyle  broken  away  and  lost.  These  are  all  typically  phytosaurian  in  form  and 
correspond  closely  with  Huene's  description  of  P.  kappfi  as  opposed  to  his  P.  rutemeyeri. 
The  general  form  is  shown  in  figure  30,  and  plate  12,  figure  c,  of  No.  7261.  All  show 
clearly  the  pit  in  the  occipital  condyle  for  the  anterior  end  of  the  notochord. 

No.  7474  is  the  smallest,  and  is  interesting  in  that  it  shows  the  lower  portions  of 
the  exoccipitals  in  position,  meeting  in  the  median  line  and  excluding  the  basioccipital 
from  any  part  in  the  foramen  magnum.  (Plate  12,  fig.  D.) 

No.  7505  is  the  next  largest.  The  exoccipitals  are  lost,  and  it  shows  clearly  the 
corrugated  articular  surfaces  on  the  basioccipital  for  the  exoccipital.  The  floor  of  the 
brain-case  is  eroded  and  the  suture  between  the  basioccipital  and  the  basisphenoid  is 
clearly  traceable  all  round  the  bone.  The  edges  of  the  shallow  hypophysial  cavity 
are  broken  away  and  the  entrance  of  the  foramina  for  the  internal  carotid  arteries  into 
the  cavity  is  very  clear.  (Plate  12,  fig.  E.) 

No.  7261  is  the  third  largest  and  the  most  perfect.  The  tubera  basioccipitalia 
are  seen  to  be  formed  by  both  the  basioccipital  and  the  basisphenoid.  The  tubera  are 


CASE 


PLATE  14 


Lci>t<>Kiichus  crosbiensis,  University  of  Michigan.     All  figures  X0.15. 

A.  Upper  surface  of  skull.         D.  Inner  side  of  the  right  lower  jaw. 

B.  Lower  surface  of  skull.         E.  Outer  side  of  the  right  lower  jaw. 

C.  Right  side  of  skull. 


THE  UPPER  TRIASSIC  OF  WESTERN  TEXAS. 


77 


prominent  and  rugose,  with  a  deep,  irregular  groove  marking  the  position  of  the  suture. 
Between  the  tubera  is  a  sharp  angulation  marking  the  line  between  junction  of  the 
basioccipital  and  the  basisphenoid,  and  along  this  the  suture  between  the  two  bones  is 
easily  traced.  On  the  sides  of  the  basioccipital,  just  posterior  to  the  basisphenoid  suture, 
there  is  a  shallow  groove  running  upward  and  backward.  Between  the  tubera  and 
basipterygoid  processes  on  either  side  are  the  large  openings  of  the  foramina  for  the 
internal  carotid  arteries.  These  foramina  run  upward  and  inward  and  open  a  little  to 
either  side  of  the  lower  end  of  the  hypophysial  cavity.  The  cavity  is  triangular  in 
section  above,  but  contracts  rapidly  below;  it  is  surprisingly  small  and  shallow.  The 
basipterygoid  processes  are  well  developed  and  point  outward  and  downward,  with  a 
smooth,  flat,  oval  face  for  the  pterygoid.  The  sphenoidal  rostrum  is  broken  away  in 
all  of  the  specimens,  but  was  evidently  vertical,  narrow,  and  of  great  extent.  In  none 
of  the  specimens  is  there  any  suggestion  of  a  composite  structure,  i.  e.,  an  upper  (pre- 
sphenoidal)  and  a  lower  (parasphenoidal)  portion,  such  as  described  and  figured  by  Huene. 


FIG.  30. 

A.  Basicranial  region,  left  side,  No.  7261,  U.  of  Mich. 

B.  Lower  side  of  same. 


X0.6. 


No.  7257tis  the  largest  of  the  specimens,  being  nearly  twice  the  size  of  No.  7474 
and  the  least  well  preserved.  It  has  lost  the  occipital  condyle  and  parts  of  the  tubera 
and  basipterygoid  processes.  The  anterior  lower  part  of  the  basioccipital  is  still  in 
position,  and  clean  breaks  show  the  suture  between  it  and  the  basisphenoid.  The 
whole  basisphenoid  is  shorter  and  higher  than  in  the  other  specimens.  The  basipterygoid 
processes  are  shorter  and  less  well  developed;  they  pointed  more  directly  backward, 
and  on  the  inner  posterior  corner  of  the  base  of  each  there  is  a  prominent  rugosity,  which 
on  the  left  side  has  the  form  of  a  pit  with  elevated  edges.  The  space  between  the  basi- 
pterygoid processes  is  marked  by  two  prominent  rugose  ridges,  which  converge  forward 
and  unite  at  the  origin  of  the  sphenoidal  rostrum.  It  would  appear  that  this  space 
between  the  processes  was  almost  vertical  instead  of  slanting  rather  steeply  upward  and 
forward,  as  in  the  other  specimens,  but  as  this  would  make  the  sphenoidal  rostrum  rise 
vertically  in  the  skull  it  is  probable  that  the  position  of  the  occipital  condyle  was  different 
from  that  it  occupies  in  the  other  specimens.  This  specimen  is  s-o  much  larger  and  so 
different  from  the  others  and  from  any  described  form  that  it  indicates,  in  all  probability, 
a  new  species,  but  it  seems  undesirable  to  give  a  new  name  to  such  imperfect  material, 
especially  as  the  large  size  suggests  the  possibility  that  the  peculiar  features  may  be 
due  to  advanced  age. 


78  NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 

DESCRIPTION   OF  THE  REMAINS  OF  DINOSAURS. 

Certain  specimens  collected  in  Crosby  County,  in  the  same  beds  with  the 
Phytosaurs,  indicate  the  presence  of  a  small  Dinosaur.  Notable  among  these  are 
a  posterior  cranial  region  (No.  7473,  University  of  Michigan)  and  a  string  of  cer- 
vical and  anterior  dorsal  vertebrae  (No.  7507).  Both  of  these  specimens  were 
collected  on  the  west  side  of  the  Blanco  River,  north  of  Cedar  Mountain,  the  first 
in  the  breaks  to  the  south  of  the  old  Spur-Crosbyton  mail-road  and  the  second  in 
the  breaks  just  north  of  that  road. 

The  cranial  region  is  well  preserved  in  a  hard  matrix  of  clay,  which  has  permitted 
the  working  out  of  the  smaller  details  and  the  foramina  of  the  region.  As  shown  in 
plate  13  D  to  F,  the  basicranial  floor  is  preserved  as  far  forward  as  the  hypophysis. 
The  distal  portions  of  the  exoccipital  opisthotics  are  lost.  The  occipital  condyle  is  nearly 
hemispherical,  with  an  extremely  short  neck.  The  portion  of  the  basioccipital  below 
the  condyle  descends  almost  vertically  and  the  posterior  edges  of  the  tubera  are  not  in 
advance  of  the  anterior  edge  of  the  condyle.  The  vertical  portion  of  the  basioccipital 
is  deeply  concave  posteriorly  and  the  lower  face  of  the  neck  of  the  condyle  is  perforated 
by  two  small  foramina  near  the  middle  line,  probably  for  nutrient  vessels.  The  sutures 
between  the  basioccipitals,  exoccipitals,  and  supraoccipitals  can  not  be  made  out. 
The  foramen  magnum  is  depressed  oval  in  outline,  with  the  transverse  axis  nearly  as 
great  as  the  width  of  the  condyle.  The  supraoccipital  is  smooth,  slightly  concave,  and 
slants  upward  and  forward  to  the  rough,  incomplete  edge,  which  must  have  been  very 
near  to  the  articular  surface  for  the  bones  above.  As  described  by  Huene  in  Anchisaurus, 
the  exoccipital  has  three  ridges;  one  runs  inward  and  backward  to  the  upper  outer 
edge  of  the  condyle,  one  downward  on  the  outer  side  to  the  tubera,  and  one  outward 
and  backward  to  form  the  lower  edge  of  the  opisthotics.  In  the  angle  formed  by  the 
last  two  there  is  the  good-sized  opening  of  the  foramen  for  the  XII  nerve.  This  foramen 
can  be  traced  on  the  broken  surface  of  the  bone  to  its  opening  on  the  inner  side,  not 
far  within  the  edge  of  the  foramen  magnum. 

The  lateral  view  of  the  specimen  (plate  13  E)  displays  the  peculiar  characters 
of  the  skull  most  strikingly.  The  inner  portion  of  the  opisthotic  and  the  prootic  meet 
in  a  smooth  concave  surface  which  is  inclined  to  the  posterior  surface  of  the  supraoccipital, 
so  that  the  two  would  meet  at  a  sharp  angle.  The  beginning  of  the  opisthotic  shows  that 
that  bone  extended  outward  and  backward  and  slightly  upward.  On  its  lower  side  is 
a  deep  groove  which  leads  into  the  surprisingly  large  otic  cavity.  Below  this  cavity  the 
basisphenoid  extends  downward,  terminating  in  the  long  and  slender  basipterygoid 
processes.  The  distal  ends  of  these  processes  are  broken  away,  so  that  it  is  impossible  to 
determine  the  nature  of  the  articulation  with  the  pterygoids.  The  basipterygoid  pro- 
cesses are  rounded  and  heavier  behind,  but  become  very  thin  anteriorly;  the  anterior 
edges  are  broken  away,  but  it  appears  that  the  processes  of  the  two  sides  came  together, 
or  very  nearly  so,  in  the  median  line.  Between  and  beneath  the  anterior  portions  of  the 
process  is  a  large  cavity  extending  forward  as  far  as  the  groove  on  the  side  of  the  basi- 
sphenoid described  below.  This  cavity  is  apparently  blind;  no  openings  in  its  wall  have 
been  detected,  though  an  artificial  opening  was  made  by  the  needle  in  the  thin  anterior 
portion.  The  side  of  the  basisphenoid  is  peculiar.  In  the  broken  condition  of  the  speci- 
men it  appeared  as  if  the  bone  were  composed  of  two  parts,  an  anterior  overlapping  below 
on  to  the  posterior  part,  which  in  turn  overlapped  in  the  same  way  upon  the  basioccipital  ; 
this  appearance,  however,  is  less  apparent  when  the  upper  half  of  the  brain-case  is 
put  in  place,  for  the  upper  part  of  the  apparent  groove  on  the  side  of  the  basisphenoid 
is  resolved  into  a  part  of  a  foramen.  The  anterior  portion  of  the  basisphenoid  has 


THE   UPPER   TRIASSIC   OF   WESTERN   TEXAS.  79 

the  sides  slanting  obliquely  inward  and  downward  until  they  meet  in  a  thin  edge 
below;  the  extreme  terminus  of  this  edge  is  broken  away.  Posteriorly  there  is  a  break 
between  the  edge  and  the  anterior  portion  of  the  posterior  part  of  the  basisphenoid, 
formed  by  the  approximating  edges  of  the  basipterygoid  processes.  This  break  empha- 
sizes the  apparent  bipartite  character  of  the  basisphenoid.  On  the  sides  of  the  basi- 
sphenoid and  marking  the  line  between  the  two  portions  is  a  groove,  which  is  very  pro- 
nounced below  and  becomes  very  shallow  in  its  upper  third.  A  little  below  the  middle 
of  the  course  of  the  groove  there  is  a  deep  extension  forward  of  the  cavity  which  runs  a 
little  downward  as  well  as  forward.  This  cavity  is  so  deep  that  exploration  is  difficult, 
but  apparently  its  anterior  end  communicates  by  a  very  small  foramen  with  the  hypo- 
physial  cavity  below.  Above  this  cavity  the  groove  becomes  very  shallow  and  finally 
terminates  in  a  foramen  which  penetrates  the  wall  of  the  brain-case.  This  foramen 
is  the  common  terminus  of  two  leads,  one  the  groove  just  described  and  the  other  a 
foramen  which  in  the  specimen  is  first  detected  on  the  broken  lower  outer  edge  of  the 
opisthotic;  the  distal  termination  of  the  latter  is  not  determinable.  From  its  position 
on  the  inner  wall  of  the  brain-case  the  common  foramen  is  evidently  the  outlet  for  the 
VII  nerve.  The  deep  vacuities  at  the  middle  of  the  course  of  the  groove  are  probably 
the  inlets  of  the  internal  carotid  arteries.  Anterior  to  the  grooves  the  sides  of  the 
anterior  portion  of  the  basisphenoid  contract  rapidly  into  the  thin  ridge  on  the  lower 
edge;  above  this  sharp  edge  and  covered  by  it  is  a  cavity,  conical  in  form,  with  its  posterior 
end  almost  a  point  and  the  anterior  part  much  larger  in  diameter.  The  anterior  edge  of 
this  opening  is  apparently  coincident  with  an  opening  into  the  brain-cavity  and  so  must 
be  the  cavity  for  the  pituitary  body.  On  the  sides  of  the  bones,  just  about  opposite 
the  cavity  for  the  pituitary  body,  there  are  two  small  foramina  on  each  side,  probably 
for  blood-vessels.  On  the  upper  edge,  just  anterior  to  the  openings  of  the  VII  nerves, 
there  is  a  large  foramen  on  each  side  which  can  only  be  the  opening  for  the  V  nerve. 
The  anterior  portion  of  the  basisphenoid  described  is  in  the  position  of  the  bone  which 
is  called  by  Osborn  the  orbitosphenoid. 

On  the  inner  side  of  the  brain-case  there  is  visible  a  decided  angulation  between 
the  parts  of  the  floor  formed  by  the  basioccipital  and  the  basisphenoid;  near  the  middle 
of  the  flat  floor  formed  by  the  basisphenoid,  but  nearer  the  anterior  than  the  posterior 
edge,  there  is  a  pair  of  small  foramina  in  the  position  usually  occupied  by  the  VI  nerve. 
The  posterior  part  of  the  inner  side  of  the  brain-case  wall  is  marked  by  a  decided  swelling 
which  sheltered  the  inner  ear.  The  exact  interpretation  of  this  region  is  impossible, 
because  of  the  slight  injury  to  the  bone  on  both  sides.  Beneath  the  swelling  marking 
the  position  of  the  canals  of  the  ear  there  is  an  opening  of  considerable  size  on  both  sides, 
which  leads  directly  into  the  large  cavities  on  the  sides  of  the  skull  at  the  inner  end  of 
the  opisthotic.  This  opening  in  all  probability  was  the  outlet  for  the  IX-XI  nerves. 

Just  anterior  to  the  swelling  marking  the  position  of  the  canals  there  is  a  shallow 
notch  with  an  elongate  form,  its  greatest  diameter  vertical;  it  is  apparent  that  the  bottom 
of  this  notch  has  not  been  reached  in  cleaning,  and  it  seems  very  probable  that  there  is 
a  small  foramen  leading  from  it  into  the  region  of  the  otic  canals;  if  this  is  correct,  this 
notch  marks  the  position  of  the  escape  of  the  VIII  nerve;  but  a  similar  notch  is  shown  by 
Osborn,  in  his  figure  of  Tyrannosaurus,  just  posterior  to  the  otic  region,  which  he  regards 
as  marking  an  evagination  of  the  dura  mater  into  the  cranial  wall.  Almost  directly 
above  these  notches  and  near  the  anterior  edge  of  the  preserved  portion  of  the  cranial 
wall  there  is  a  second  deep  pit  on  each  side  which  can  not  be  traced  through  the  bone 
and  appear  to  be  blind;  these  are  almost  exactly  in  the  position  marked  by  Osborn,  in 
his  figure  of  Tyrannosaurus,  as  other  evaginations  of  the  dura  mater. 

This  fragment  of  a  skull  is  so  radically  different  from  that  of  the  Phytosaurs  found 
in  the  same  beds,  and  corresponds  so  well  with  the  figures  and  descriptions,  so  far  as  they 
have  been  given,  of  the  same  region  in  the  primitive  Theropodous  Dinosaurs,  that  there 


80  NEW  REPTILES  AND   STEGOCEPHALIANS   FROM 

can  be  very  little  doubt  of  its  subordinal  position.  Little  can  be  said  of  its  generic 
position.  The  only  other  Dinosaur  remains  that  have  been  found  in  the  Triassic  of  the 
Southwest  are  the  very  incomplete  remains  of  forms  described  by  Cope  as  Coelophysis 
from  the  Gallina  Mountains  in  New  Mexico.  These  forms  are  placed  in  the  family 
Cceluridse,  occurring  in  the  Upper  Keuper  in  Europe  and  in  the  Upper  Triassic  in  North 
America.  For  the  present,  this  fragmentary  skull  and  the  few  vertebrae  described  below 
may  be  provisionally  placed  in  or  near  this  genus,  especially  as  the  remains  of  Phytosaurs 
and  Stegocephalians  which  occur  in  the  same  beds  indicate  an  Upper  Triassic  age. 

In  1887,  Cope1  described  the  remains  of  a  small  genus  of  Dinosaur  from  New  Mexico, 
which  he  at  first  placed  in  the  genus  Ccelurus,  later  referred  to  Tanystrophceus,  and 
finally  placed  in  a  new  genus,  Coelophysis.2  Three  species  were  described — longicollis, 
bauri,  and  willistoni.  According  to  Huene,  the  type  material  of  the  last  species  has 
been  lost. 

During  the  summer  of  1921  the  author  collected  a  series  of  small  Dinosaur  vertebra 
(No.  7507,  University  of  Michigan),  a  few  miles  north  of  Cedar  Mountain,  in  Crosby 
County,  Texas,  in  the  same  beds  with  the  Upper  Triassic  Phytosaurs  and  Stegocephalians 
described  in  this  paper.  When  found  the  vertebras  were  in  position,  but  were  fully 
exposed  and  badly  broken  as  they  lay  on  the  crumbled  surface  of  a  light  cream-colored 
clay.  The  anterior  and  posterior  members  of  the  series  and  many  small  fragments 
of  ribs  were  loosened  from  the  rest  of  the  series  and  had  slipped  down  the  face  of  a  rather 
steep  slope.  Because  of  the  crumbled  condition  of  the  matrix,  it  was  impossible  to 
collect  the  specimen  in  a  block;  it  could  only  be  taken  up  with  as  much  of  the  matrix 
as  possible,  which  was  filled  with  the  minute  fragments  which  had  been  separated  from 
the  vertebrae.  Reassembling  the  specimen  has  been  a  very  long  and  tedious  piece  of 
work  and  has  been  only  fairly  successful  as  yet,  but  enough  has  been  accomplished  to 
show  the  character  of  the  vertebrae.  The  specimen  is  of  importance,  as  it  is  the  largest 
series  of  Dinosaur  vertebrae  yet  found  in  a  free  condition  in  the  Triassic  of  North  America. 

The  series  contains  20  complete  vertebra?,  with  the  remains  of  two  very  imperfect 
ones.  Of  the  series,  the  first  four  are  elongated  and  very  similar  to  those  figured  by 
Huene  as  characteristic  of  Anchisaurus  coelurus  and  Ccelophysis.  The  fifth  of  the  series 
is  shorter  and  shows  for  the  first  time  in  the  series  a  well-developed  transverse  process; 
it  is  probable  that  the  first  four  are  cervicals  and  the  remainder  dorsals.  There  is  no 
certain  indication  of  the  sacrals;  the  transverse  processes  of  the  last  two  are  indicated 
only  by  the  bases,  but  these  are  well  formed  and  not  the  bases  of  sacral  ribs.  In  Anchi- 
saurus there  are  14  dorsals  and  probably  9  cervicals.  According  to  Osborn3  there  are 
23  presacrals  in  Struthiomimus,  Allosaurus,  and  Tyrannosaurus.  In  Struthiomimus, 
with  10  cervicals,  the  first  dorsal  is  indicated  by  the  presence  of  the  first  free  rib  according 
to  Osborn.  If  we  accept  this  as  a  criterion,  the  fifth  of  the  series  here  described  would 
be  the  first  dorsal  and  there  would  be  16  dorsals,  a  number  that  seems  excessive,  but  can 
be  questioned  only  by  considering  the  last  two  as  sacrals,  a  proceeding  that  is  not  war- 
ranted by  the  form  of  the  vertebrae. 

The  first  of  the  series  (sixth  (?)  cervical)  was  found  a  little  separated  from  the 
series,  washed  down  the  bank,  and  the  zygapophyses  and  the  neural  arch  have  not  been 
reassembled.  It  can  be  seen,  however,  that  the  zygapophyses  were  elongate,  low,  and 
horizontal  and  that  the  neural  spine  was  low.  The  centrum  is  elongate,  the  anterior 
face  concave  and  broader  than  the  posterior;  its  borders  have  been  injured  by  decay. 
The  lower  face  of  the  centrum  is  broader  anteriorly  and  nearly  flat  at  the  anterior  end; 

1  Cope,  E.  D.,  American  Naturalist,  pp.  36/-3t38,  1887. 

2  The  literature  of  this  genus  is  given  by  Hay,  Bulletin  United  States  Geological  Survey,  No.  179,  p.  493,  1902, 

and  Huene,  Geol.  u.  Paleont.  Abhdlg.,  N.  F.,  Bd.  vin,  s.  118,  1906.     In  the  latter  paper  figures  are  given 
of  some  of  the  specimens  and  the  species  are  in  part  redescribed. 

3  Osborn,  H.  F.,  Bulletin  American  Museum  Natural  History,  vol.  35,  art.  43,  p.  735,  1917. 


I  Hi:    UPPER   TRIASSIC    OF   WESTERN    TEXAS. 


81 


posteriorly  the  lower  face  becomes  rounded  from  side  to  side,  with  no  trace  of  a  keel 
or  lateral  ridges  or  angles.  The  posterior  portion  of  the  centrum  descends  slightly, 
maintaining  its  rounded  outline.  The  posterior  face  has  an  oval  outline,  being  higher 
than  wide,  due  to  the  development  of  a  lip  on  the  lower  edge.  It  is  concave,  but  less 
so  than  the  anterior  face,  and  slants  from  above  downward  and  backward.  Length 
of  the  base  of  the  centrum,  52  mm. 

The  second  of  the  series  (seventh  (?)  cervical)  is  much  more  complete.  It  lacks 
the  anterior  zygapophyses  and  the  neural  spine.  In  this  vertebra  the  anterior  face  is 
complete;  it  is  deeply  concave  and  is  inclined  parallel  to  the  posterior  face  of  the  preceding 
vertebra,  i.  e.,  from  above  downward  and  backward.  On  either  side  of  the  anterior 
portion  of  the  centrum  there  are  two  processes;  the  upper  begins  as  a  low  ridge  at 
about  the  middle  point  of 
the  side  of  the  centrum  Id 

and  extends  forward  to  the 
edge  of  the  anterior  face, 
becoming  more  prominent 
during  its  advance.  The 
second  process,  below  the 
first,  is  shorter,  not  over 
12  mm.,  and  heavier;  it 
continues  out  upon  the 
edges  of  the  anterior  face 
of  the  centrum,  forming  a 
narrow  triangular  face 
which  looks  downward 
and  outward  and  slightly 
forward.  These  two  pro- 
cesses are  distinct,  as 
shown  by  several  vertebrae, 
but  are  very  suggestive  of 
the  complete  arch  figure  by  Marsh1  in  Coelurus  and  described  by  Cope  and  Huene  in 
Ccelophysis  longicollis.  It  is  possible,  even  probable,  that  there  was  such  a  complete  arch 
in  the  anterior  cervicals,  but  in  the  posterior  portion  of  the  cervical  series  the  arch  has 
broken  into  distinct  diapophysis  and  parapophysis.  The  posterior  zygapophyses  are 
depressed  and  elongate,  extending  back  nearly  as  far  as  the  upper  edge  of  the  posterior 
face  of  the  centrum.  The  rest  of  the  vertebra  is  much  like  the  preceding  one.  Length 
of  the  base  of  the  centrum,  52  mm. 

The  third  of  the  series  (eighth  (?)  cervical)  has  the  upper  process  on  the  side  of  the 
centrum  stronger  and  extending  outward  more  than  in  the  second;  the  process  is  a  little 
higher  on  the  side  of  the  centrum.  The  lower  process  is  shorter  and  has  a  larger  face. 
The  anterior  zygapophyses  are  preserved;  they  are  horizontal,  heavy,  and  extend  well 
forward  of  the  anterior  face  of  the  centrum.  Length  of  the  base  of  the  centrum,  44  mm. 

The  fourth  of  the  series  (ninth  (?)  cervical)  has  the  anterior  zygapophyses  locked 
with  the  posterior  ones  of  the  third ;  they  are  still  nearly  horizontal,  but  are  slightly  inclined 
upward.  The  upper  process  on  the  side  of  the  centrum  is  now  very  strong  and  stands 
well  out  from  the  vertebra;  it  is  so  high  upon  the  centrum  that  its  lower  edge  is  but 
slightly  below  the  lower  face  of  the  neural  canal.  The  anterior  edge  of  the  centrum 
is  injured,  but  it  can  be  seen  that  the  lower  process  is  now  but  a  triangular  face  on  the 
lower  edge  of  the  face.  Length  of  the  base  of  the  centrum,  42  mm. 

1  Marsh,  O.  C.,  Dinosaurs  of  North  America,  Sixteenth  Annual  Report  U.  S.  Geological  Survey,  plate  vii, 
figs.  2,  2o,  1896. 


FIG.  31. 

Cervical  and  dorsal  vertebrae  of  a  small  Dinosaur,  Ccdophysis,  sp.  No.  7507, 

U.  of  Mich.     X  0.5. 


82 


NEW   REPTILES   AND    STEGOCEPHALIANS   FROM 


This  structure  of  the  posterior  cervicals  is  very  similar  to  the  condition  found  in 
Sellosaurus  hermannianus  Huene.1 

The  fifth  of  the  series  (first  (?)  dorsal)  has  the  upper  process  on  the  side  of  the 
neural  arch ;  only  its  proximal  portion  is  preserved,  but  it  is  apparent  that  it  stood  well 
out  from  the  side  of  the  arch,  forming  a  distinct  transverse  process.  The  lower  process  is 
a  triangular  face  on  the  lower  edge  of  the  anterior  face  of  the  centrum.  In  this  vertebra 
the  zygapophyses  and  the  neural  spine  have  not  been  replaced.  Due  in  part,  but  not 
entirely,  to  compression,  the  centrum  is  notably  shorter  and  heavier  than  the  preceding 
one  and  the  posterior  face  of  the  centrum  does  not  descend  lower  than  the  anterior. 
The  faces  of  the  centrum  are  now  vertical  and  larger  than  in  the  cervical  series.  Length 
of  the  base  of  the  centrum,  27  mm. 

The  sixth  of  the  series  has  a  well-developed  transverse  process  which  stands  out  at 
right  angles  from  the  high  neural  arch.  This  process  is  supported  by  two  ridges  running 
from  the  upper  edges  of  the  anterior  and  posterior  faces  of  the  centrum  to  its  base; 
between  these  ridges  and  on  either  side  of  the  base  of  the  processes  are  deep  pits.  The 
lower  process  is  still  visible  as  a  small  facet  on  the  lower  edge  of  the  anterior  face  of  the 
centrum.  The  neural  arch  is  high  and  the  anterior  and  posterior  zygapophyses  rise  at 
a  considerable  angle  instead  of  lying  horizontal.  Length  of  base  of  centrum,  27  mm. 

The  seventh  of  the  series  has  well-developed  transverse  processes;  the  extremities 
are  not  replaced,  but  the  base  shows  that  they  stood  out  at  right  angles  to  the  neural 
arch.  The  base  is  supported  by  four  ridges  running  respectively  from  the  anterior  and 
posterior  zygapophyses  and  from  the  upper  edges  of  the  anterior  and  posterior  faces 
of  the  centrum.  Between  these  ridges,  on  the  anterior  and  posterior  faces  of  the  base 
of  the  transverse  process,  there  are  deep  pits.  Upon  this  vertebra  appears  the  last 
trace  of  the  lower  process.  The  zygapophyses  have  not  been  replaced,  but  it  is  evident 
that  they  rose  at  a  decided  angle  from  the  neural  arch.  The  lower  edge  of  the  centrum 
is  injured,  but  its  length  is  approximately  32  mm. 

From  this  point  in  the  series  backward  the  vertebrae  do  not  change  radically. 
The  transverse  processes  increase  slightly  in  length  and  then  decrease;  the  longest  are 
upon  the  tenth  to  the  thirteenth.  The  zygapophyses  are  very  steeply  inclined  upward 
on  the  ninth  and  tenth  and  are  less  steeply  inclined  in  the  posterior  vertebrae.  The 
centra  become  gradually  heavier  toward  the  posterior  end  of  the  series,  and  the  bases  of 
the  transverse  processes  are  shorter  anterio-posteriorly,  due  to  the  atrophy  of  the  support- 
ing ridges.  In  none  of  the  vertebras  is  there  any  sign  of  a  median  keel  on  the  centra 
or  of  any  lateral  ridges.  The  length  of  the  base  of  the  centrum  of  each  is  as  follows: 


8th 

mm. 
31 

13th 

mm. 
37 

17th 

mm. 
39 

9th 

33 

18th   . 

38 

10th 

33 

15th 

36 

19th 

36 

llth 

36 

16th 

38 

20th 

.  .  35 

12th 

.   35 

These  measurements  are  as  accurate  as  possible,  but  are  not  quite  as  in  nature 
because  of  slight  compression,  breakage,  etc.,  in  the  specimen. 

Fractures  in  the  mid-line  of  several  vertebras  show  that  the  centrum  was  hollow, 
but  not  so  thin-walled  as  in  Ccelurus.  The  ribs  are  uniformly  single-headed;  one  attached 
to  the  fourteenth  vertebra  has  a  thin  head  7  mm.  wide;  other  rib-heads  not  located,  but 
apparently  belonging  to  more  anterior  vertebrae,  are  nearly  twice  as  broad.  The  shaft 
of  the  rib  in  certain  parts  of  the  series  was  T-shaped  in  section.  The  ribs  are  so  badly 
broken  and  the  ends  so  injured  by  decay  that  only  portions  have  as  yet  been  reassembled. 

1  Huene,  F.  v.,  Neues  Jahrb.  f.  Gcol.  Min.  u.  Pal.  Jahrg.,  1915,  No.  1,  Taf.  111. 


THE   UPPER   TRIASSIC   OF   WESTERN   TEXAS. 


83 


These  vertebrae  must  be  tentatively  assumed  to  belong  to  a  small  Dinosaur,  such 
as  bore  the  skull,  the  posterior  portion  of  which  is  described  above,  as  the  sizes  of  the 
two  specimens  correspond  very  closely,  and  as  they  were  found  in  the  same  beds  and  but 
2  or  3  miles  apart.  Until  further  evidence  is 
found,  the  vertebrae  may  be  assigned  to  the 
genus  Ccelophysis. 

A  femur,  No.  3396,  University  of 
Michigan  (fig.  32),  is  rather  puzzling.  It  is 
42.16  centimeters  in  length.  Compared  with 
a  typical  phytosaurian  femur  (No.  3395),  it 
is  much  heavier  at  the  articular  ends  and  the 
articular  surfaces  are  better  formed.  The 
relation  of  the  long  axes  of  the  articular  ends 
is  different  in  the  two  forms;  in  No.  3395 
the  axes  are  nearly  at  right  angles,  so  that 
when  the  head  was  in  the  socket  of  the  pelvis 
the  anterior  face  of  the  lower  end  was  pre- 
sented almost  directly  forward ;  in  the  second 
femur  the  axes  are  at  an  angle  of  60°,  so  that 
the  anterior  face  of  the  lower  end  was  pre- 
sented inward  as  well  as  forward. 

In  the  phytosaurian  femur  the  tro- 
chanter  has  the  characteristic  form  of  an  oval 
elevation  with  a  depressed  center,  and  the 
lower  end  has  a  simple  articular  region  ob- 
scurely divided  into  two  parts.  In  the  other 
femur  the  trochanter  is  simply  a  heavy  rugose 
area  but  little  raised  above  the  rest  of  the 
bone;  the  lower  end  is  heavy  and  divided 
into  two  areas,  but  on  the  posterior  side  of  the 
outer  part  there  is  a  prominent  process  which 
is  continued  upward  on  the  shaft  of  the  bone 
as  a  ridge  for  some  distance.  This  femur  has  a  very  dinosaurian  aspect,  resembling 
in  many  details  the  figures  of  the  femora  of  Plateosaurus  and  Gressylosaurus  from  the 
Triassic  of  Europe,  and,  so  far  as  can  be  determined,  the  femur  of  Anchisaurus  from  the 
Triassic  of  North  America.  No  remains  of  Dinosaurs  of  the  size  indicated  by  this  femur 
have  been  found  in  the  Triassic  of  the  western  portion  of  North  America;  Ccelophysis 
Cope  was  decidedly  smaller.  It  is  to  be  hoped  that  more  material  revealing  the  skeleton 
of  this  Dinosaur  will  be  found. 

COPROLITES. 

There  are  several  types  of  coprolites  contained  in  the  collection.  The  number  found 
in  the  Holmes  Creek  region  is  very  large  and  the  condition  of  preservation  is  in  most 
cases  very  good. 

The  first  type  is  that  which  must  be  assigned  to  the  larger  reptiles  and  stegocepha- 
lians.  These  vary  from  5  cm.  in  length  to  as  much  as  15  or  18  cms.  The  form  is  generally 
regular,  with  smooth  surfaces.  In  none  that  have  been  found  has  it  been  possible  to 
detect  anything,  such  as  comminuted  bones  or  scales,  that  would  indicate  the  nature 
of  the  food.  Microscopic  sections  have  not  been  made  of  any  of  tlio  coprolites. 


B. 


FIG.  32. 

Left  femur  of  a  Dinosaur, 
U.  of  Mich.     X  0.25. 
Posterior  view  of  same. 


front  «ew,  No.  3396. 


84 


NEW   REPTILES   AND    STEGOCEPHALIANS. 


The  second  type  is  small,  ranging  from  1  cm.  to  as  much  as  7,  in  extreme  cases, 
in  length.  They  show  very  perfectly  the  spiral  nature  of  the  coprolite;  two  very  good 
specimens  are  shown  in  figure  33  A  and  B.  It  seems  probable  that  these  are  the  coprolites 


FIG.  33. 

A  and  B.  Two  coprolites  showing  trace  of  the  spiral  valve.     X  1. 

C  and  D.  Two  coprolites  showing  the  longitudinal  ridges.     XI. 

E.  Figure  of  a  tooth  of  an  unknown  form,  No.  7506,  U.  of  Mich.     XI. 

of  the  Dipnoan  fish  of  the  region,  but  in  the  light  of  the  great  number  of  the  coprolites 
it  is  strange  that  not  more  of  the  skeleton  of  the  fish  has  been  found;  only  two  teeth  and 
no  other  parts  of  the  skeleton  have  been  found.1 

The  third  type  of  coprolite  is  very  different  from  the  other  two.  These  range  from 
2.5  to  7  cm.  in  length.  They  are  all  somewhat  curved,  sometimes  approaching  a  cres- 
centic  form.  In  many,  especially  of  the  smaller  coprolites  of  this  type,  the  outer  side  of 
the  curve  is  marked  by  deep  and  regular  grooves  very  evenly  spaced  (fig.  33  c).  This 
is  so  striking  that  when  the  first  fragment  of  one  was  found  it  was  suspected  that  it 
represented,  the  surface  of  a  Cephalopod  shell.  In  most  of  the  larger  coprolites  of  this 
type  the  markings  are  very  obscure  or  wanting,  but  the  curved  form  is  always  character- 
istic. In  the  larger  forms  there  is  frequently  an  additional  part  of  the  coprolite  which 
fits  over  the  end  as  a  cap  or  cloak  (fig.  33  D).  It  is  impossible  to  associate  this  type  of 
coprolite  with  any  definite  group  of  animals;  the  only  suggestion  that  can  be  made  is 
that  in  many  amphibians  the  distal  portion  of  the  rectum  is  thrown  into  parallel  linear 
folds — just  such  an  arrangement  as  would  make  linear  markings  upon  the  foecal  mass. 

INCERT.E  SEDIS. 

A  small  fragment  of  a  jaw  contains  a  very  singularly  shaped  tooth  which  the  author 
has  been  unable  to  identify,  or  even  to  determine  its  relationships.  As  shown  in  figure 
33  E,  the  tooth  is  elongate  oval  in  section,  with  the  greatest  diameter  parallel  to  the 
length  of  the  jaw.  In  general  outline  it  is  reminiscent  of  the  teeth  of  the  Permo- 
Carboniferous  reptile  Diadectes,  but  the  upper  edge  is  contracted,  slightly  concave  antero- 
posteriorly,  and  has  a  narrow,  flat  surface,  slightly  inclined  toward  the  outer  (?)  side. 
The  outer  (?)  side  of  the  tooth  is  slightly  concave,  and  there  is  a  swelling  at  the  base 
and  then  a  sharp  contraction.  The  tooth  is  without  root  and  attached  directly  to  the  bone. 
The  base  of  a  second  tooth  shows  the  rather  spongy  character  of  the  base  (fig.  33  E). 

1  Case,  E.  C.,  Occasional  Papers  of  the  Museum  of  Zoology,  University  of  Michigan,  No.  101,  Apr.  9,  1921. 


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Case,   E.G. 

New  reptiles  and 
stegocephalians  from 
the  Upper  Triassic 
of  western  Texas. 

PHYSICAL 
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QE861 
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Case,  E.G. 

New  reptiles  and 
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